NFToken_test.cpp

#include <test/jtx.h>
 
#include <xrpl/basics/random.h>
#include <xrpl/protocol/Feature.h>
#include <xrpl/protocol/jss.h>
#include <xrpl/tx/transactors/nft/NFTokenUtils.h>
 
#include <initializer_list>
 
namespace xrpl {
 
class NFTokenBaseUtil_test : public beast::unit_test::suite
{
    // Helper function that returns the number of NFTs minted by an issuer.
    static std::uint32_t
    mintedCount(test::jtx::Env const& env, test::jtx::Account const& issuer)
    {
        std::uint32_t ret{0};
        if (auto const sleIssuer = env.le(issuer))
            ret = sleIssuer->at(~sfMintedNFTokens).value_or(0);
        return ret;
    }
 
    // Helper function that returns the number of an issuer's burned NFTs.
    static std::uint32_t
    burnedCount(test::jtx::Env const& env, test::jtx::Account const& issuer)
    {
        std::uint32_t ret{0};
        if (auto const sleIssuer = env.le(issuer))
            ret = sleIssuer->at(~sfBurnedNFTokens).value_or(0);
        return ret;
    }
 
    // Helper function that returns the number of nfts owned by an account.
    static std::uint32_t
    nftCount(test::jtx::Env& env, test::jtx::Account const& acct)
    {
        Json::Value params;
        params[jss::account] = acct.human();
        params[jss::type] = "state";
        Json::Value nfts = env.rpc("json", "account_nfts", to_string(params));
        return nfts[jss::result][jss::account_nfts].size();
    };
 
    // Helper function that returns the number of tickets held by an account.
    static std::uint32_t
    ticketCount(test::jtx::Env const& env, test::jtx::Account const& acct)
    {
        std::uint32_t ret{0};
        if (auto const sleAcct = env.le(acct))
            ret = sleAcct->at(~sfTicketCount).value_or(0);
        return ret;
    }
 
    // Helper function returns the close time of the parent ledger.
    static std::uint32_t
    lastClose(test::jtx::Env& env)
    {
        return env.current()->header().parentCloseTime.time_since_epoch().count();
    }
 
    void
    testEnabled(FeatureBitset features)
    {
        testcase("Enabled");
 
        using namespace test::jtx;
        {
            // If the NFT amendment is enabled all NFT-related
            // facilities should be available.
            Env env{*this, features};
            Account const& master = env.master;
 
            BEAST_EXPECT(ownerCount(env, master) == 0);
            BEAST_EXPECT(mintedCount(env, master) == 0);
            BEAST_EXPECT(burnedCount(env, master) == 0);
 
            uint256 const nftId0{token::getNextID(env, env.master, 0u)};
            env(token::mint(env.master, 0u));
            env.close();
            BEAST_EXPECT(ownerCount(env, master) == 1);
            BEAST_EXPECT(mintedCount(env, master) == 1);
            BEAST_EXPECT(burnedCount(env, master) == 0);
 
            env(token::burn(env.master, nftId0));
            env.close();
            BEAST_EXPECT(ownerCount(env, master) == 0);
            BEAST_EXPECT(mintedCount(env, master) == 1);
            BEAST_EXPECT(burnedCount(env, master) == 1);
 
            uint256 const nftId1{token::getNextID(env, env.master, 0u, tfTransferable)};
            env(token::mint(env.master, 0u), txflags(tfTransferable));
            env.close();
            BEAST_EXPECT(ownerCount(env, master) == 1);
            BEAST_EXPECT(mintedCount(env, master) == 2);
            BEAST_EXPECT(burnedCount(env, master) == 1);
 
            Account const alice{"alice"};
            env.fund(XRP(10000), alice);
            env.close();
            uint256 const aliceOfferIndex = keylet::nftoffer(alice, env.seq(alice)).key;
            env(token::createOffer(alice, nftId1, XRP(1000)), token::owner(master));
            env.close();
 
            BEAST_EXPECT(ownerCount(env, master) == 1);
            BEAST_EXPECT(mintedCount(env, master) == 2);
            BEAST_EXPECT(burnedCount(env, master) == 1);
 
            BEAST_EXPECT(ownerCount(env, alice) == 1);
            BEAST_EXPECT(mintedCount(env, alice) == 0);
            BEAST_EXPECT(burnedCount(env, alice) == 0);
 
            env(token::acceptBuyOffer(master, aliceOfferIndex));
            env.close();
 
            BEAST_EXPECT(ownerCount(env, master) == 0);
            BEAST_EXPECT(mintedCount(env, master) == 2);
            BEAST_EXPECT(burnedCount(env, master) == 1);
 
            BEAST_EXPECT(ownerCount(env, alice) == 1);
            BEAST_EXPECT(mintedCount(env, alice) == 0);
            BEAST_EXPECT(burnedCount(env, alice) == 0);
        }
    }
 
    void
    testMintReserve(FeatureBitset features)
    {
        // Verify that the reserve behaves as expected for minting.
        testcase("Mint reserve");
 
        using namespace test::jtx;
 
        Env env{*this, features};
        Account const alice{"alice"};
        Account const minter{"minter"};
 
        // Fund alice and minter enough to exist, but not enough to meet
        // the reserve for creating their first NFT.
        auto const acctReserve = env.current()->fees().reserve;
        auto const incReserve = env.current()->fees().increment;
        auto const baseFee = env.current()->fees().base;
 
        env.fund(acctReserve, alice, minter);
        env.close();
 
        BEAST_EXPECT(env.balance(alice) == acctReserve);
        BEAST_EXPECT(env.balance(minter) == acctReserve);
        BEAST_EXPECT(ownerCount(env, alice) == 0);
        BEAST_EXPECT(ownerCount(env, minter) == 0);
 
        // alice does not have enough XRP to cover the reserve for an NFT
        // page.
        env(token::mint(alice, 0u), ter(tecINSUFFICIENT_RESERVE));
        env.close();
 
        BEAST_EXPECT(ownerCount(env, alice) == 0);
        BEAST_EXPECT(mintedCount(env, alice) == 0);
        BEAST_EXPECT(burnedCount(env, alice) == 0);
 
        // Pay alice almost enough to make the reserve for an NFT page.
        env(pay(env.master, alice, incReserve + drops(baseFee - 1)));
        env.close();
 
        // A lambda that checks alice's ownerCount, mintedCount, and
        // burnedCount all in one fell swoop.
        auto checkAliceOwnerMintedBurned = [&env, this, &alice](
                                               std::uint32_t owners,
                                               std::uint32_t minted,
                                               std::uint32_t burned,
                                               int line) {
            auto oneCheck = [line, this](char const* type, std::uint32_t found, std::uint32_t exp) {
                if (found == exp)
                {
                    pass();
                }
                else
                {
                    std::stringstream ss;
                    ss << "Wrong " << type << " count.  Found: " << found << "; Expected: " << exp;
                    fail(ss.str(), __FILE__, line);
                }
            };
            oneCheck("owner", ownerCount(env, alice), owners);
            oneCheck("minted", mintedCount(env, alice), minted);
            oneCheck("burned", burnedCount(env, alice), burned);
        };
 
        // alice still does not have enough XRP for the reserve of an NFT
        // page.
        env(token::mint(alice, 0u), ter(tecINSUFFICIENT_RESERVE));
        env.close();
 
        checkAliceOwnerMintedBurned(0, 0, 0, __LINE__);
 
        // Pay alice enough to make the reserve for an NFT page.
        env(pay(env.master, alice, drops(baseFee + 1)));
        env.close();
 
        // Now alice can mint an NFT.
        env(token::mint(alice));
        env.close();
 
        checkAliceOwnerMintedBurned(1, 1, 0, __LINE__);
 
        // Alice should be able to mint an additional 31 NFTs without
        // any additional reserve requirements.
        for (int i = 1; i < 32; ++i)
        {
            env(token::mint(alice));
            checkAliceOwnerMintedBurned(1, i + 1, 0, __LINE__);
        }
 
        // That NFT page is full.  Creating an additional NFT page requires
        // additional reserve.
        env(token::mint(alice), ter(tecINSUFFICIENT_RESERVE));
        env.close();
        checkAliceOwnerMintedBurned(1, 32, 0, __LINE__);
 
        // Pay alice almost enough to make the reserve for an NFT page.
        env(pay(env.master, alice, incReserve + drops(baseFee * 33 - 1)));
        env.close();
 
        // alice still does not have enough XRP for the reserve of an NFT
        // page.
        env(token::mint(alice), ter(tecINSUFFICIENT_RESERVE));
        env.close();
        checkAliceOwnerMintedBurned(1, 32, 0, __LINE__);
 
        // Pay alice enough to make the reserve for an NFT page.
        env(pay(env.master, alice, drops(baseFee + 1)));
        env.close();
 
        // Now alice can mint an NFT.
        env(token::mint(alice));
        env.close();
        checkAliceOwnerMintedBurned(2, 33, 0, __LINE__);
 
        // alice burns the NFTs she created: check that pages consolidate
        std::uint32_t seq = 0;
 
        while (seq < 33)
        {
            env(token::burn(alice, token::getID(env, alice, 0, seq++)));
            env.close();
            checkAliceOwnerMintedBurned(((33 - seq) != 0u) ? 1 : 0, 33, seq, __LINE__);
        }
 
        // alice burns a non-existent NFT.
        env(token::burn(alice, token::getID(env, alice, 197, 5)), ter(tecNO_ENTRY));
        env.close();
        checkAliceOwnerMintedBurned(0, 33, 33, __LINE__);
 
        // That was fun!  Now let's see what happens when we let someone
        // else mint NFTs on alice's behalf.  alice gives permission to
        // minter.
        env(token::setMinter(alice, minter));
        env.close();
        BEAST_EXPECT(env.le(alice)->getAccountID(sfNFTokenMinter) == minter.id());
 
        // A lambda that checks minter's and alice's ownerCount,
        // mintedCount, and burnedCount all in one fell swoop.
        auto checkMintersOwnerMintedBurned = [&env, this, &alice, &minter](
                                                 std::uint32_t aliceOwners,
                                                 std::uint32_t aliceMinted,
                                                 std::uint32_t aliceBurned,
                                                 std::uint32_t minterOwners,
                                                 std::uint32_t minterMinted,
                                                 std::uint32_t minterBurned,
                                                 int line) {
            auto oneCheck =
                [this](char const* type, std::uint32_t found, std::uint32_t exp, int line) {
                    if (found == exp)
                    {
                        pass();
                    }
                    else
                    {
                        std::stringstream ss;
                        ss << "Wrong " << type << " count.  Found: " << found
                           << "; Expected: " << exp;
                        fail(ss.str(), __FILE__, line);
                    }
                };
            oneCheck("alice owner", ownerCount(env, alice), aliceOwners, line);
            oneCheck("alice minted", mintedCount(env, alice), aliceMinted, line);
            oneCheck("alice burned", burnedCount(env, alice), aliceBurned, line);
            oneCheck("minter owner", ownerCount(env, minter), minterOwners, line);
            oneCheck("minter minted", mintedCount(env, minter), minterMinted, line);
            oneCheck("minter burned", burnedCount(env, minter), minterBurned, line);
        };
 
        std::uint32_t nftSeq = 33;
 
        // Pay minter almost enough to make the reserve for an NFT page.
        env(pay(env.master, minter, incReserve - drops(1)));
        env.close();
        checkMintersOwnerMintedBurned(0, 33, nftSeq, 0, 0, 0, __LINE__);
 
        // minter still does not have enough XRP for the reserve of an NFT
        // page. Just for grins (and code coverage), minter mints NFTs that
        // include a URI.
        env(token::mint(minter),
            token::issuer(alice),
            token::uri("uri"),
            ter(tecINSUFFICIENT_RESERVE));
        env.close();
        checkMintersOwnerMintedBurned(0, 33, nftSeq, 0, 0, 0, __LINE__);
 
        // Pay minter enough to make the reserve for an NFT page.
        env(pay(env.master, minter, drops(baseFee + 1)));
        env.close();
 
        // Now minter can mint an NFT for alice.
        env(token::mint(minter), token::issuer(alice), token::uri("uri"));
        env.close();
        checkMintersOwnerMintedBurned(0, 34, nftSeq, 1, 0, 0, __LINE__);
 
        // Minter should be able to mint an additional 31 NFTs for alice
        // without any additional reserve requirements.
        for (int i = 1; i < 32; ++i)
        {
            env(token::mint(minter), token::issuer(alice), token::uri("uri"));
            checkMintersOwnerMintedBurned(0, i + 34, nftSeq, 1, 0, 0, __LINE__);
        }
 
        // Pay minter almost enough for the reserve of an additional NFT
        // page.
        env(pay(env.master, minter, incReserve + drops(baseFee * 32 - 1)));
        env.close();
 
        // That NFT page is full.  Creating an additional NFT page requires
        // additional reserve.
        env(token::mint(minter),
            token::issuer(alice),
            token::uri("uri"),
            ter(tecINSUFFICIENT_RESERVE));
        env.close();
        checkMintersOwnerMintedBurned(0, 65, nftSeq, 1, 0, 0, __LINE__);
 
        // Pay minter enough for the reserve of an additional NFT page.
        env(pay(env.master, minter, drops(baseFee + 1)));
        env.close();
 
        // Now minter can mint an NFT.
        env(token::mint(minter), token::issuer(alice), token::uri("uri"));
        env.close();
        checkMintersOwnerMintedBurned(0, 66, nftSeq, 2, 0, 0, __LINE__);
 
        // minter burns the NFTs she created.
        while (nftSeq < 65)
        {
            env(token::burn(minter, token::getID(env, alice, 0, nftSeq++)));
            env.close();
            checkMintersOwnerMintedBurned(
                0, 66, nftSeq, ((65 - seq) != 0u) ? 1 : 0, 0, 0, __LINE__);
        }
 
        // minter has one more NFT to burn.  Should take her owner count to
        // 0.
        env(token::burn(minter, token::getID(env, alice, 0, nftSeq++)));
        env.close();
        checkMintersOwnerMintedBurned(0, 66, nftSeq, 0, 0, 0, __LINE__);
 
        // minter burns a non-existent NFT.
        env(token::burn(minter, token::getID(env, alice, 2009, 3)), ter(tecNO_ENTRY));
        env.close();
        checkMintersOwnerMintedBurned(0, 66, nftSeq, 0, 0, 0, __LINE__);
    }
 
    void
    testMintMaxTokens(FeatureBitset features)
    {
        // Make sure that an account cannot cause the sfMintedNFTokens
        // field to wrap by minting more than 0xFFFF'FFFF tokens.
        testcase("Mint max tokens");
 
        using namespace test::jtx;
 
        Account const alice{"alice"};
        Env env{*this, features};
        env.fund(XRP(1000), alice);
        env.close();
 
        // We're going to hack the ledger in order to avoid generating
        // 4 billion or so NFTs.  Because we're hacking the ledger we
        // need alice's account to have non-zero sfMintedNFTokens and
        // sfBurnedNFTokens fields.  This prevents an exception when the
        // AccountRoot template is applied.
        {
            uint256 const nftId0{token::getNextID(env, alice, 0u)};
            env(token::mint(alice, 0u));
            env.close();
 
            env(token::burn(alice, nftId0));
            env.close();
        }
 
        // Note that we're bypassing almost all of the ledger's safety
        // checks with this modify() call.  If you call close() between
        // here and the end of the test all the effort will be lost.
        env.app().getOpenLedger().modify([&alice](OpenView& view, beast::Journal j) {
            // Get the account root we want to hijack.
            auto const sle = view.read(keylet::account(alice.id()));
            if (!sle)
                return false;  // This would be really surprising!
 
            // Just for sanity's sake we'll check that the current value
            // of sfMintedNFTokens matches what we expect.
            auto replacement = std::make_shared<SLE>(*sle, sle->key());
            if (replacement->getFieldU32(sfMintedNFTokens) != 1)
                return false;  // Unexpected test conditions.
 
            // Sequence number is generated by sfFirstNFTokenSequence +
            // sfMintedNFTokens. We can replace the two fields with any
            // numbers as long as they add up to the largest valid number.
            // In our case, sfFirstNFTokenSequence is set to the largest
            // valid number, and sfMintedNFTokens is set to zero.
            (*replacement)[sfFirstNFTokenSequence] = 0xFFFF'FFFE;
            (*replacement)[sfMintedNFTokens] = 0x0000'0000;
            view.rawReplace(replacement);
            return true;
        });
 
        // See whether alice is at the boundary that causes an error.
        env(token::mint(alice, 0u), ter(tesSUCCESS));
        env(token::mint(alice, 0u), ter(tecMAX_SEQUENCE_REACHED));
    }
 
    void
    testMintInvalid(FeatureBitset features)
    {
        // Explore many of the invalid ways to mint an NFT.
        testcase("Mint invalid");
 
        using namespace test::jtx;
 
        Env env{*this, features};
        Account const alice{"alice"};
        Account const minter{"minter"};
 
        // Fund alice and minter enough to exist, but not enough to meet
        // the reserve for creating their first NFT.  Account reserve for unit
        // tests is 200 XRP, not 20.
        env.fund(XRP(200), alice, minter);
        env.close();
 
        env(token::mint(alice, 0u), ter(tecINSUFFICIENT_RESERVE));
        env.close();
 
        // Fund alice enough to start minting NFTs.
        env(pay(env.master, alice, XRP(1000)));
        env.close();
 
        //----------------------------------------------------------------------
        // preflight
 
        // Set a negative fee.
        env(token::mint(alice, 0u), fee(STAmount(10ull, true)), ter(temBAD_FEE));
 
        // Set an invalid flag.
        env(token::mint(alice, 0u), txflags(0x00008000), ter(temINVALID_FLAG));
 
        // Can't set a transfer fee if the NFT does not have the tfTRANSFERABLE
        // flag set.
        env(token::mint(alice, 0u), token::xferFee(maxTransferFee), ter(temMALFORMED));
 
        // Set a bad transfer fee.
        env(token::mint(alice, 0u),
            token::xferFee(maxTransferFee + 1),
            txflags(tfTransferable),
            ter(temBAD_NFTOKEN_TRANSFER_FEE));
 
        // Account can't also be issuer.
        env(token::mint(alice, 0u), token::issuer(alice), ter(temMALFORMED));
 
        // Invalid URI: zero length.
        env(token::mint(alice, 0u), token::uri(""), ter(temMALFORMED));
 
        // Invalid URI: too long.
        env(token::mint(alice, 0u),
            token::uri(std::string(maxTokenURILength + 1, 'q')),
            ter(temMALFORMED));
 
        //----------------------------------------------------------------------
        // preclaim
 
        // Non-existent issuer.
        env(token::mint(alice, 0u), token::issuer(Account("demon")), ter(tecNO_ISSUER));
 
        //----------------------------------------------------------------------
        // doApply
 
        // Existent issuer, but not given minting permission
        env(token::mint(minter, 0u), token::issuer(alice), ter(tecNO_PERMISSION));
    }
 
    void
    testBurnInvalid(FeatureBitset features)
    {
        // Explore many of the invalid ways to burn an NFT.
        testcase("Burn invalid");
 
        using namespace test::jtx;
 
        Env env{*this, features};
        Account const alice{"alice"};
        Account const buyer{"buyer"};
        Account const minter{"minter"};
        Account const gw("gw");
        IOU const gwAUD(gw["AUD"]);
 
        // Fund alice and minter enough to exist and create an NFT, but not
        // enough to meet the reserve for creating their first NFTOffer.
        // Account reserve for unit tests is 200 XRP, not 20.
        env.fund(XRP(250), alice, buyer, minter, gw);
        env.close();
        BEAST_EXPECT(ownerCount(env, alice) == 0);
 
        uint256 const nftAlice0ID = token::getNextID(env, alice, 0, tfTransferable);
        env(token::mint(alice, 0u), txflags(tfTransferable));
        env.close();
        BEAST_EXPECT(ownerCount(env, alice) == 1);
 
        //----------------------------------------------------------------------
        // preflight
 
        // Set a negative fee.
        env(token::burn(alice, nftAlice0ID), fee(STAmount(10ull, true)), ter(temBAD_FEE));
        env.close();
        BEAST_EXPECT(ownerCount(env, alice) == 1);
 
        // Set an invalid flag.
        env(token::burn(alice, nftAlice0ID), txflags(0x00008000), ter(temINVALID_FLAG));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 0);
 
        //----------------------------------------------------------------------
        // preclaim
 
        // Try to burn a token that doesn't exist.
        env(token::burn(alice, token::getID(env, alice, 0, 1)), ter(tecNO_ENTRY));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 0);
 
        // Can't burn a token with many buy or sell offers.  But that is
        // verified in testManyNftOffers().
 
        //----------------------------------------------------------------------
        // doApply
    }
 
    void
    testCreateOfferInvalid(FeatureBitset features)
    {
        testcase("Invalid NFT offer create");
 
        using namespace test::jtx;
 
        Env env{*this, features};
        Account const alice{"alice"};
        Account const buyer{"buyer"};
        Account const gw("gw");
        IOU const gwAUD(gw["AUD"]);
 
        // Fund alice enough to exist and create an NFT, but not
        // enough to meet the reserve for creating their first NFTOffer.
        // Account reserve for unit tests is 200 XRP, not 20.
        env.fund(XRP(250), alice, buyer, gw);
        env.close();
        BEAST_EXPECT(ownerCount(env, alice) == 0);
 
        uint256 const nftAlice0ID = token::getNextID(env, alice, 0, tfTransferable, 10);
        env(token::mint(alice, 0u), txflags(tfTransferable), token::xferFee(10));
        env.close();
        BEAST_EXPECT(ownerCount(env, alice) == 1);
 
        uint256 const nftXrpOnlyID = token::getNextID(env, alice, 0, tfOnlyXRP | tfTransferable);
        env(token::mint(alice, 0), txflags(tfOnlyXRP | tfTransferable));
        env.close();
        BEAST_EXPECT(ownerCount(env, alice) == 1);
 
        uint256 const nftNoXferID = token::getNextID(env, alice, 0);
        env(token::mint(alice, 0));
        env.close();
        BEAST_EXPECT(ownerCount(env, alice) == 1);
 
        //----------------------------------------------------------------------
        // preflight
 
        // buyer burns a fee, so they no longer have enough XRP to cover the
        // reserve for a token offer.
        env(noop(buyer));
        env.close();
 
        // buyer tries to create an NFTokenOffer, but doesn't have the reserve.
        env(token::createOffer(buyer, nftAlice0ID, XRP(1000)),
            token::owner(alice),
            ter(tecINSUFFICIENT_RESERVE));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 0);
 
        // Set a negative fee.
        env(token::createOffer(buyer, nftAlice0ID, XRP(1000)),
            fee(STAmount(10ull, true)),
            ter(temBAD_FEE));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 0);
 
        // Set an invalid flag.
        env(token::createOffer(buyer, nftAlice0ID, XRP(1000)),
            txflags(0x00008000),
            ter(temINVALID_FLAG));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 0);
 
        // Set an invalid amount.
        env(token::createOffer(buyer, nftXrpOnlyID, buyer["USD"](1)), ter(temBAD_AMOUNT));
        env(token::createOffer(buyer, nftAlice0ID, buyer["USD"](0)), ter(temBAD_AMOUNT));
        env(token::createOffer(buyer, nftXrpOnlyID, drops(0)), ter(temBAD_AMOUNT));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 0);
 
        // Set a bad expiration.
        env(token::createOffer(buyer, nftAlice0ID, buyer["USD"](1)),
            token::expiration(0),
            ter(temBAD_EXPIRATION));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 0);
 
        // Invalid Owner field and tfSellToken flag relationships.
        // A buy offer must specify the owner.
        env(token::createOffer(buyer, nftXrpOnlyID, XRP(1000)), ter(temMALFORMED));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 0);
 
        // A sell offer must not specify the owner; the owner is implicit.
        env(token::createOffer(alice, nftXrpOnlyID, XRP(1000)),
            token::owner(alice),
            txflags(tfSellNFToken),
            ter(temMALFORMED));
        env.close();
        BEAST_EXPECT(ownerCount(env, alice) == 1);
 
        // An owner may not offer to buy their own token.
        env(token::createOffer(alice, nftXrpOnlyID, XRP(1000)),
            token::owner(alice),
            ter(temMALFORMED));
        env.close();
        BEAST_EXPECT(ownerCount(env, alice) == 1);
 
        // The destination may not be the account submitting the transaction.
        env(token::createOffer(alice, nftXrpOnlyID, XRP(1000)),
            token::destination(alice),
            txflags(tfSellNFToken),
            ter(temMALFORMED));
        env.close();
        BEAST_EXPECT(ownerCount(env, alice) == 1);
 
        // The destination must be an account already established in the ledger.
        env(token::createOffer(alice, nftXrpOnlyID, XRP(1000)),
            token::destination(Account("demon")),
            txflags(tfSellNFToken),
            ter(tecNO_DST));
        env.close();
        BEAST_EXPECT(ownerCount(env, alice) == 1);
 
        //----------------------------------------------------------------------
        // preclaim
 
        // The new NFTokenOffer may not have passed its expiration time.
        env(token::createOffer(buyer, nftXrpOnlyID, XRP(1000)),
            token::owner(alice),
            token::expiration(lastClose(env)),
            ter(tecEXPIRED));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 0);
 
        // The nftID must be present in the ledger.
        env(token::createOffer(buyer, token::getID(env, alice, 0, 1), XRP(1000)),
            token::owner(alice),
            ter(tecNO_ENTRY));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 0);
 
        // The nftID must be present in the ledger of a sell offer too.
        env(token::createOffer(alice, token::getID(env, alice, 0, 1), XRP(1000)),
            txflags(tfSellNFToken),
            ter(tecNO_ENTRY));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 0);
 
        // buyer must have the funds to pay for their offer.
        env(token::createOffer(buyer, nftAlice0ID, gwAUD(1000)),
            token::owner(alice),
            ter(tecNO_LINE));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 0);
 
        env(trust(buyer, gwAUD(1000)));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 1);
        env.close();
 
        // Issuer (alice) must have a trust line for the offered funds.
        env(token::createOffer(buyer, nftAlice0ID, gwAUD(1000)),
            token::owner(alice),
            ter(tecNO_LINE));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 1);
 
        // Give alice the needed trust line, but freeze it.
        env(trust(gw, alice["AUD"](999), tfSetFreeze));
        env.close();
 
        // Issuer (alice) must have a trust line for the offered funds and
        // the trust line may not be frozen.
        env(token::createOffer(buyer, nftAlice0ID, gwAUD(1000)),
            token::owner(alice),
            ter(tecFROZEN));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 1);
 
        // Unfreeze alice's trustline.
        env(trust(gw, alice["AUD"](999), tfClearFreeze));
        env.close();
 
        // Can't transfer the NFT if the transferable flag is not set.
        env(token::createOffer(buyer, nftNoXferID, gwAUD(1000)),
            token::owner(alice),
            ter(tefNFTOKEN_IS_NOT_TRANSFERABLE));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 1);
 
        // Give buyer the needed trust line, but freeze it.
        env(trust(gw, buyer["AUD"](999), tfSetFreeze));
        env.close();
 
        env(token::createOffer(buyer, nftAlice0ID, gwAUD(1000)),
            token::owner(alice),
            ter(tecFROZEN));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 1);
 
        // Unfreeze buyer's trust line, but buyer has no actual gwAUD.
        // to cover the offer.
        env(trust(gw, buyer["AUD"](999), tfClearFreeze));
        env(trust(buyer, gwAUD(1000)));
        env.close();
 
        env(token::createOffer(buyer, nftAlice0ID, gwAUD(1000)),
            token::owner(alice),
            ter(tecUNFUNDED_OFFER));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 1);  // the trust line.
 
        //----------------------------------------------------------------------
        // doApply
 
        // Give buyer almost enough AUD to cover the offer...
        env(pay(gw, buyer, gwAUD(999)));
        env.close();
 
        // However buyer doesn't have enough XRP to cover the reserve for
        // an NFT offer.
        env(token::createOffer(buyer, nftAlice0ID, gwAUD(1000)),
            token::owner(alice),
            ter(tecINSUFFICIENT_RESERVE));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 1);
 
        // Give buyer almost enough XRP to cover the reserve.
        auto const baseFee = env.current()->fees().base;
        env(pay(env.master, buyer, XRP(50) + drops(baseFee * 12 - 1)));
        env.close();
 
        env(token::createOffer(buyer, nftAlice0ID, gwAUD(1000)),
            token::owner(alice),
            ter(tecINSUFFICIENT_RESERVE));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 1);
 
        // Give buyer just enough XRP to cover the reserve for the offer.
        env(pay(env.master, buyer, drops(baseFee + 1)));
        env.close();
 
        // We don't care whether the offer is fully funded until the offer is
        // accepted.  Success at last!
        env(token::createOffer(buyer, nftAlice0ID, gwAUD(1000)),
            token::owner(alice),
            ter(tesSUCCESS));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 2);
    }
 
    void
    testCancelOfferInvalid(FeatureBitset features)
    {
        testcase("Invalid NFT offer cancel");
 
        using namespace test::jtx;
 
        Env env{*this, features};
        Account const alice{"alice"};
        Account const buyer{"buyer"};
        Account const gw("gw");
        IOU const gwAUD(gw["AUD"]);
 
        env.fund(XRP(1000), alice, buyer, gw);
        env.close();
        BEAST_EXPECT(ownerCount(env, alice) == 0);
 
        uint256 const nftAlice0ID = token::getNextID(env, alice, 0, tfTransferable);
        env(token::mint(alice, 0u), txflags(tfTransferable));
        env.close();
        BEAST_EXPECT(ownerCount(env, alice) == 1);
 
        // This is the offer we'll try to cancel.
        uint256 const buyerOfferIndex = keylet::nftoffer(buyer, env.seq(buyer)).key;
        env(token::createOffer(buyer, nftAlice0ID, XRP(1)), token::owner(alice), ter(tesSUCCESS));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 1);
 
        //----------------------------------------------------------------------
        // preflight
 
        // Set a negative fee.
        env(token::cancelOffer(buyer, {buyerOfferIndex}),
            fee(STAmount(10ull, true)),
            ter(temBAD_FEE));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 1);
 
        // Set an invalid flag.
        env(token::cancelOffer(buyer, {buyerOfferIndex}),
            txflags(0x00008000),
            ter(temINVALID_FLAG));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 1);
 
        // Empty list of tokens to delete.
        {
            Json::Value jv = token::cancelOffer(buyer);
            jv[sfNFTokenOffers.jsonName] = Json::arrayValue;
            env(jv, ter(temMALFORMED));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == 1);
        }
 
        // List of tokens to delete is too long.
        {
            std::vector<uint256> const offers(maxTokenOfferCancelCount + 1, buyerOfferIndex);
 
            env(token::cancelOffer(buyer, offers), ter(temMALFORMED));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == 1);
        }
 
        // Duplicate entries are not allowed in the list of offers to cancel.
        env(token::cancelOffer(buyer, {buyerOfferIndex, buyerOfferIndex}), ter(temMALFORMED));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 1);
 
        // Provide neither offers to cancel nor a root index.
        env(token::cancelOffer(buyer), ter(temMALFORMED));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 1);
 
        //----------------------------------------------------------------------
        // preclaim
 
        // Make a non-root directory that we can pass as a root index.
        env(pay(env.master, gw, XRP(5000)));
        env.close();
        for (std::uint32_t i = 1; i < 34; ++i)
        {
            env(offer(gw, XRP(i), gwAUD(1)));
            env.close();
        }
 
        {
            // gw attempts to cancel a Check as through it is an NFTokenOffer.
            auto const gwCheckId = keylet::check(gw, env.seq(gw)).key;
            env(check::create(gw, env.master, XRP(300)));
            env.close();
 
            env(token::cancelOffer(gw, {gwCheckId}), ter(tecNO_PERMISSION));
            env.close();
 
            // Cancel the check so it doesn't mess up later tests.
            env(check::cancel(gw, gwCheckId));
            env.close();
        }
 
        // gw attempts to cancel an offer they don't have permission to cancel.
        env(token::cancelOffer(gw, {buyerOfferIndex}), ter(tecNO_PERMISSION));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 1);
 
        //----------------------------------------------------------------------
        // doApply
        //
        // The tefBAD_LEDGER conditions are too hard to test.
        // But let's see a successful offer cancel.
        env(token::cancelOffer(buyer, {buyerOfferIndex}));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 0);
    }
 
    void
    testAcceptOfferInvalid(FeatureBitset features)
    {
        testcase("Invalid NFT offer accept");
 
        using namespace test::jtx;
 
        Env env{*this, features};
        Account const alice{"alice"};
        Account const buyer{"buyer"};
        Account const gw("gw");
        IOU const gwAUD(gw["AUD"]);
 
        env.fund(XRP(1000), alice, buyer, gw);
        env.close();
        BEAST_EXPECT(ownerCount(env, alice) == 0);
        BEAST_EXPECT(ownerCount(env, buyer) == 0);
 
        uint256 const nftAlice0ID = token::getNextID(env, alice, 0, tfTransferable);
        env(token::mint(alice, 0u), txflags(tfTransferable));
        env.close();
        uint8_t aliceCount = 1;
        BEAST_EXPECT(ownerCount(env, alice) == aliceCount);
 
        uint256 const nftXrpOnlyID = token::getNextID(env, alice, 0, tfOnlyXRP | tfTransferable);
        env(token::mint(alice, 0), txflags(tfOnlyXRP | tfTransferable));
        env.close();
        BEAST_EXPECT(ownerCount(env, alice) == aliceCount);
 
        uint256 const nftNoXferID = token::getNextID(env, alice, 0);
        env(token::mint(alice, 0));
        env.close();
        BEAST_EXPECT(ownerCount(env, alice) == aliceCount);
 
        // alice creates sell offers for her nfts.
        uint256 const plainOfferIndex = keylet::nftoffer(alice, env.seq(alice)).key;
        env(token::createOffer(alice, nftAlice0ID, XRP(10)), txflags(tfSellNFToken));
        env.close();
        aliceCount++;
        BEAST_EXPECT(ownerCount(env, alice) == aliceCount);
 
        uint256 const audOfferIndex = keylet::nftoffer(alice, env.seq(alice)).key;
        env(token::createOffer(alice, nftAlice0ID, gwAUD(30)), txflags(tfSellNFToken));
        env.close();
        aliceCount++;
        BEAST_EXPECT(ownerCount(env, alice) == aliceCount);
 
        uint256 const xrpOnlyOfferIndex = keylet::nftoffer(alice, env.seq(alice)).key;
        env(token::createOffer(alice, nftXrpOnlyID, XRP(20)), txflags(tfSellNFToken));
        env.close();
        aliceCount++;
        BEAST_EXPECT(ownerCount(env, alice) == aliceCount);
 
        uint256 const noXferOfferIndex = keylet::nftoffer(alice, env.seq(alice)).key;
        env(token::createOffer(alice, nftNoXferID, XRP(30)), txflags(tfSellNFToken));
        env.close();
        aliceCount++;
        BEAST_EXPECT(ownerCount(env, alice) == aliceCount);
 
        // alice creates a sell offer that will expire soon.
        uint256 const aliceExpOfferIndex = keylet::nftoffer(alice, env.seq(alice)).key;
        env(token::createOffer(alice, nftNoXferID, XRP(40)),
            txflags(tfSellNFToken),
            token::expiration(lastClose(env) + 5));
        env.close();
        aliceCount++;
        BEAST_EXPECT(ownerCount(env, alice) == aliceCount);
 
        // buyer creates a Buy offer that will expire soon.
        uint256 const buyerExpOfferIndex = keylet::nftoffer(buyer, env.seq(buyer)).key;
        env(token::createOffer(buyer, nftAlice0ID, XRP(40)),
            token::owner(alice),
            token::expiration(lastClose(env) + 5));
        env.close();
        uint8_t buyerCount = 1;
        BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
        //----------------------------------------------------------------------
        // preflight
 
        // Set a negative fee.
        env(token::acceptSellOffer(buyer, noXferOfferIndex),
            fee(STAmount(10ull, true)),
            ter(temBAD_FEE));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
        // Set an invalid flag.
        env(token::acceptSellOffer(buyer, noXferOfferIndex),
            txflags(0x00008000),
            ter(temINVALID_FLAG));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
        // Supply nether an sfNFTokenBuyOffer nor an sfNFTokenSellOffer field.
        {
            Json::Value jv = token::acceptSellOffer(buyer, noXferOfferIndex);
            jv.removeMember(sfNFTokenSellOffer.jsonName);
            env(jv, ter(temMALFORMED));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
        }
 
        // A buy offer may not contain a sfNFTokenBrokerFee field.
        {
            Json::Value jv = token::acceptBuyOffer(buyer, noXferOfferIndex);
            jv[sfNFTokenBrokerFee.jsonName] = STAmount(500000).getJson(JsonOptions::none);
            env(jv, ter(temMALFORMED));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
        }
 
        // A sell offer may not contain a sfNFTokenBrokerFee field.
        {
            Json::Value jv = token::acceptSellOffer(buyer, noXferOfferIndex);
            jv[sfNFTokenBrokerFee.jsonName] = STAmount(500000).getJson(JsonOptions::none);
            env(jv, ter(temMALFORMED));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
        }
 
        // A brokered offer may not contain a negative or zero brokerFee.
        env(token::brokerOffers(buyer, noXferOfferIndex, xrpOnlyOfferIndex),
            token::brokerFee(gwAUD(0)),
            ter(temMALFORMED));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
        //----------------------------------------------------------------------
        // preclaim
 
        // The buy offer must be non-zero.
        env(token::acceptBuyOffer(buyer, beast::zero), ter(tecOBJECT_NOT_FOUND));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
        // The buy offer must be present in the ledger.
        uint256 const missingOfferIndex = keylet::nftoffer(alice, 1).key;
        env(token::acceptBuyOffer(buyer, missingOfferIndex), ter(tecOBJECT_NOT_FOUND));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
        // The buy offer must not have expired.
        // NOTE: this is only a preclaim check with the
        // fixExpiredNFTokenOfferRemoval amendment disabled.
        env(token::acceptBuyOffer(alice, buyerExpOfferIndex), ter(tecEXPIRED));
        env.close();
        if (features[fixExpiredNFTokenOfferRemoval])
        {
            buyerCount--;
        }
        BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
        // The sell offer must be non-zero.
        env(token::acceptSellOffer(buyer, beast::zero), ter(tecOBJECT_NOT_FOUND));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
        // The sell offer must be present in the ledger.
        env(token::acceptSellOffer(buyer, missingOfferIndex), ter(tecOBJECT_NOT_FOUND));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
        // The sell offer must not have expired.
        // NOTE: this is only a preclaim check with the
        // fixExpiredNFTokenOfferRemoval amendment disabled.
        env(token::acceptSellOffer(buyer, aliceExpOfferIndex), ter(tecEXPIRED));
        env.close();
        // Alice's count is decremented by one when the expired offer is
        // removed.
        if (features[fixExpiredNFTokenOfferRemoval])
        {
            aliceCount--;
        }
        BEAST_EXPECT(ownerCount(env, alice) == aliceCount);
        BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
        //----------------------------------------------------------------------
        // preclaim brokered
 
        // alice and buyer need trustlines before buyer can to create an
        // offer for gwAUD.
        env(trust(alice, gwAUD(1000)));
        env(trust(buyer, gwAUD(1000)));
        env.close();
        env(pay(gw, buyer, gwAUD(30)));
        env.close();
        aliceCount++;
        buyerCount++;
        BEAST_EXPECT(ownerCount(env, alice) == aliceCount);
        BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
        BEAST_EXPECT(ownerCount(env, alice) == aliceCount);
        BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
        // We're about to exercise offer brokering, so we need
        // corresponding buy and sell offers.
        {
            // buyer creates a buy offer for one of alice's nfts.
            uint256 const buyerOfferIndex = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftAlice0ID, gwAUD(29)), token::owner(alice));
            env.close();
            buyerCount++;
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            // gw attempts to broker offers that are not for the same token.
            env(token::brokerOffers(gw, buyerOfferIndex, xrpOnlyOfferIndex),
                ter(tecNFTOKEN_BUY_SELL_MISMATCH));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            // gw attempts to broker offers that are not for the same currency.
            env(token::brokerOffers(gw, buyerOfferIndex, plainOfferIndex),
                ter(tecNFTOKEN_BUY_SELL_MISMATCH));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            // In a brokered offer, the buyer must offer greater than or
            // equal to the selling price.
            env(token::brokerOffers(gw, buyerOfferIndex, audOfferIndex),
                ter(tecINSUFFICIENT_PAYMENT));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            // Remove buyer's offer.
            env(token::cancelOffer(buyer, {buyerOfferIndex}));
            env.close();
            buyerCount--;
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
        }
        {
            // buyer creates a buy offer for one of alice's nfts.
            uint256 const buyerOfferIndex = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftAlice0ID, gwAUD(31)), token::owner(alice));
            env.close();
            buyerCount++;
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            // Broker sets their fee in a denomination other than the one
            // used by the offers
            env(token::brokerOffers(gw, buyerOfferIndex, audOfferIndex),
                token::brokerFee(XRP(40)),
                ter(tecNFTOKEN_BUY_SELL_MISMATCH));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            // Broker fee way too big.
            env(token::brokerOffers(gw, buyerOfferIndex, audOfferIndex),
                token::brokerFee(gwAUD(31)),
                ter(tecINSUFFICIENT_PAYMENT));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            // Broker fee is smaller, but still too big once the offer
            // seller's minimum is taken into account.
            env(token::brokerOffers(gw, buyerOfferIndex, audOfferIndex),
                token::brokerFee(gwAUD(1.5)),
                ter(tecINSUFFICIENT_PAYMENT));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            // Remove buyer's offer.
            env(token::cancelOffer(buyer, {buyerOfferIndex}));
            env.close();
            buyerCount--;
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
        }
        //----------------------------------------------------------------------
        // preclaim buy
        {
            // buyer creates a buy offer for one of alice's nfts.
            uint256 const buyerOfferIndex = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftAlice0ID, gwAUD(30)), token::owner(alice));
            env.close();
            buyerCount++;
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            // Don't accept a buy offer if the sell flag is set.
            env(token::acceptBuyOffer(buyer, plainOfferIndex), ter(tecNFTOKEN_OFFER_TYPE_MISMATCH));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == aliceCount);
 
            // An account can't accept its own offer.
            env(token::acceptBuyOffer(buyer, buyerOfferIndex),
                ter(tecCANT_ACCEPT_OWN_NFTOKEN_OFFER));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            // An offer acceptor must have enough funds to pay for the offer.
            env(pay(buyer, gw, gwAUD(30)));
            env.close();
            BEAST_EXPECT(env.balance(buyer, gwAUD) == gwAUD(0));
            env(token::acceptBuyOffer(alice, buyerOfferIndex), ter(tecINSUFFICIENT_FUNDS));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            // alice gives her NFT to gw, so alice no longer owns nftAlice0.
            {
                uint256 const offerIndex = keylet::nftoffer(alice, env.seq(alice)).key;
                env(token::createOffer(alice, nftAlice0ID, XRP(0)), txflags(tfSellNFToken));
                env.close();
                env(token::acceptSellOffer(gw, offerIndex));
                env.close();
                BEAST_EXPECT(ownerCount(env, alice) == aliceCount);
            }
            env(pay(gw, buyer, gwAUD(30)));
            env.close();
 
            // alice can't accept a buy offer for an NFT she no longer owns.
            env(token::acceptBuyOffer(alice, buyerOfferIndex), ter(tecNO_PERMISSION));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            // Remove buyer's offer.
            env(token::cancelOffer(buyer, {buyerOfferIndex}));
            env.close();
            buyerCount--;
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
        }
        //----------------------------------------------------------------------
        // preclaim sell
        {
            // buyer creates a buy offer for one of alice's nfts.
            uint256 const buyerOfferIndex = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftXrpOnlyID, XRP(30)), token::owner(alice));
            env.close();
            buyerCount++;
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            // Don't accept a sell offer without the sell flag set.
            env(token::acceptSellOffer(alice, buyerOfferIndex),
                ter(tecNFTOKEN_OFFER_TYPE_MISMATCH));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == aliceCount);
 
            // An account can't accept its own offer.
            env(token::acceptSellOffer(alice, plainOfferIndex),
                ter(tecCANT_ACCEPT_OWN_NFTOKEN_OFFER));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            // The seller must currently be in possession of the token they
            // are selling.  alice gave nftAlice0ID to gw.
            env(token::acceptSellOffer(buyer, plainOfferIndex), ter(tecNO_PERMISSION));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            // gw gives nftAlice0ID back to alice.  That allows us to check
            // buyer attempting to accept one of alice's offers with
            // insufficient funds.
            {
                uint256 const offerIndex = keylet::nftoffer(gw, env.seq(gw)).key;
                env(token::createOffer(gw, nftAlice0ID, XRP(0)), txflags(tfSellNFToken));
                env.close();
                env(token::acceptSellOffer(alice, offerIndex));
                env.close();
                BEAST_EXPECT(ownerCount(env, alice) == aliceCount);
            }
            env(pay(buyer, gw, gwAUD(30)));
            env.close();
            BEAST_EXPECT(env.balance(buyer, gwAUD) == gwAUD(0));
            env(token::acceptSellOffer(buyer, audOfferIndex), ter(tecINSUFFICIENT_FUNDS));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
        }
 
        //----------------------------------------------------------------------
        // doApply
        //
        // As far as I can see none of the failure modes are accessible as
        // long as the preflight and preclaim conditions are met.
    }
 
    void
    testMintFlagBurnable(FeatureBitset features)
    {
        // Exercise NFTs with flagBurnable set and not set.
        testcase("Mint flagBurnable");
 
        using namespace test::jtx;
 
        Env env{*this, features};
        Account const alice{"alice"};
        Account const buyer{"buyer"};
        Account const minter1{"minter1"};
        Account const minter2{"minter2"};
 
        env.fund(XRP(1000), alice, buyer, minter1, minter2);
        env.close();
        BEAST_EXPECT(ownerCount(env, alice) == 0);
 
        // alice selects minter as her minter.
        env(token::setMinter(alice, minter1));
        env.close();
 
        // A lambda that...
        //  1. creates an alice nft
        //  2. minted by minter and
        //  3. transfers that nft to buyer.
        auto nftToBuyer = [&env, &alice, &minter1, &buyer](std::uint32_t flags) {
            uint256 const nftID{token::getNextID(env, alice, 0u, flags)};
            env(token::mint(minter1, 0u), token::issuer(alice), txflags(flags));
            env.close();
 
            uint256 const offerIndex = keylet::nftoffer(minter1, env.seq(minter1)).key;
            env(token::createOffer(minter1, nftID, XRP(0)), txflags(tfSellNFToken));
            env.close();
 
            env(token::acceptSellOffer(buyer, offerIndex));
            env.close();
 
            return nftID;
        };
 
        // An NFT without flagBurnable can only be burned by its owner.
        {
            uint256 const noBurnID = nftToBuyer(0);
            env(token::burn(alice, noBurnID), token::owner(buyer), ter(tecNO_PERMISSION));
            env.close();
            env(token::burn(minter1, noBurnID), token::owner(buyer), ter(tecNO_PERMISSION));
            env.close();
            env(token::burn(minter2, noBurnID), token::owner(buyer), ter(tecNO_PERMISSION));
            env.close();
 
            BEAST_EXPECT(ownerCount(env, buyer) == 1);
            env(token::burn(buyer, noBurnID), token::owner(buyer));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == 0);
        }
        // An NFT with flagBurnable can be burned by the issuer.
        {
            uint256 const burnableID = nftToBuyer(tfBurnable);
            env(token::burn(minter2, burnableID), token::owner(buyer), ter(tecNO_PERMISSION));
            env.close();
 
            BEAST_EXPECT(ownerCount(env, buyer) == 1);
            env(token::burn(alice, burnableID), token::owner(buyer));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == 0);
        }
        // An NFT with flagBurnable can be burned by the owner.
        {
            uint256 const burnableID = nftToBuyer(tfBurnable);
            BEAST_EXPECT(ownerCount(env, buyer) == 1);
            env(token::burn(buyer, burnableID));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == 0);
        }
        // An NFT with flagBurnable can be burned by the minter.
        {
            uint256 const burnableID = nftToBuyer(tfBurnable);
            BEAST_EXPECT(ownerCount(env, buyer) == 1);
            env(token::burn(buyer, burnableID), token::owner(buyer));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == 0);
        }
        // An nft with flagBurnable may be burned by the issuers' minter,
        // who may not be the original minter.
        {
            uint256 const burnableID = nftToBuyer(tfBurnable);
            BEAST_EXPECT(ownerCount(env, buyer) == 1);
 
            env(token::setMinter(alice, minter2));
            env.close();
 
            // minter1 is no longer alice's minter, so no longer has
            // permission to burn alice's nfts.
            env(token::burn(minter1, burnableID), token::owner(buyer), ter(tecNO_PERMISSION));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == 1);
 
            // minter2, however, can burn alice's nfts.
            env(token::burn(minter2, burnableID), token::owner(buyer));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == 0);
        }
    }
 
    void
    testMintFlagOnlyXRP(FeatureBitset features)
    {
        // Exercise NFTs with flagOnlyXRP set and not set.
        testcase("Mint flagOnlyXRP");
 
        using namespace test::jtx;
 
        Env env{*this, features};
        Account const alice{"alice"};
        Account const buyer{"buyer"};
        Account const gw("gw");
        IOU const gwAUD(gw["AUD"]);
 
        // Set trust lines so alice and buyer can use gwAUD.
        env.fund(XRP(1000), alice, buyer, gw);
        env.close();
        env(trust(alice, gwAUD(1000)));
        env(trust(buyer, gwAUD(1000)));
        env.close();
        env(pay(gw, buyer, gwAUD(100)));
 
        // Don't set flagOnlyXRP and offers can be made with IOUs.
        {
            uint256 const nftIOUsOkayID{token::getNextID(env, alice, 0u, tfTransferable)};
            env(token::mint(alice, 0u), txflags(tfTransferable));
            env.close();
 
            BEAST_EXPECT(ownerCount(env, alice) == 2);
            uint256 const aliceOfferIndex = keylet::nftoffer(alice, env.seq(alice)).key;
            env(token::createOffer(alice, nftIOUsOkayID, gwAUD(50)), txflags(tfSellNFToken));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 3);
 
            BEAST_EXPECT(ownerCount(env, buyer) == 1);
            uint256 const buyerOfferIndex = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftIOUsOkayID, gwAUD(50)), token::owner(alice));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == 2);
 
            // Cancel the two offers just to be tidy.
            env(token::cancelOffer(alice, {aliceOfferIndex}));
            env(token::cancelOffer(buyer, {buyerOfferIndex}));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 2);
            BEAST_EXPECT(ownerCount(env, buyer) == 1);
 
            // Also burn alice's nft.
            env(token::burn(alice, nftIOUsOkayID));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 1);
        }
 
        // Set flagOnlyXRP and offers using IOUs are rejected.
        {
            uint256 const nftOnlyXrpID{
                token::getNextID(env, alice, 0u, tfOnlyXRP | tfTransferable)};
            env(token::mint(alice, 0u), txflags(tfOnlyXRP | tfTransferable));
            env.close();
 
            BEAST_EXPECT(ownerCount(env, alice) == 2);
            env(token::createOffer(alice, nftOnlyXrpID, gwAUD(50)),
                txflags(tfSellNFToken),
                ter(temBAD_AMOUNT));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 2);
 
            BEAST_EXPECT(ownerCount(env, buyer) == 1);
            env(token::createOffer(buyer, nftOnlyXrpID, gwAUD(50)),
                token::owner(alice),
                ter(temBAD_AMOUNT));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == 1);
 
            // However offers for XRP are okay.
            BEAST_EXPECT(ownerCount(env, alice) == 2);
            env(token::createOffer(alice, nftOnlyXrpID, XRP(60)), txflags(tfSellNFToken));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 3);
 
            BEAST_EXPECT(ownerCount(env, buyer) == 1);
            env(token::createOffer(buyer, nftOnlyXrpID, XRP(60)), token::owner(alice));
            env.close();
            BEAST_EXPECT(ownerCount(env, buyer) == 2);
        }
    }
 
    void
    testMintFlagCreateTrustLine(FeatureBitset features)
    {
        // Exercise NFTs with flagCreateTrustLines set and not set.
        testcase("Mint flagCreateTrustLines");
 
        using namespace test::jtx;
 
        Account const alice{"alice"};
        Account const becky{"becky"};
        Account const cheri{"cheri"};
        Account const gw("gw");
        IOU const gwAUD(gw["AUD"]);
        IOU const gwCAD(gw["CAD"]);
        IOU const gwEUR(gw["EUR"]);
 
        // The behavior of this test changes dramatically based on the
        // presence (or absence) of the fixRemoveNFTokenAutoTrustLine
        // amendment.  So we test both cases here.
        for (auto const& tweakedFeatures :
             {features - fixRemoveNFTokenAutoTrustLine, features | fixRemoveNFTokenAutoTrustLine})
        {
            Env env{*this, tweakedFeatures};
            env.fund(XRP(1000), alice, becky, cheri, gw);
            env.close();
 
            // Set trust lines so becky and cheri can use gw's currency.
            env(trust(becky, gwAUD(1000)));
            env(trust(cheri, gwAUD(1000)));
            env(trust(becky, gwCAD(1000)));
            env(trust(cheri, gwCAD(1000)));
            env(trust(becky, gwEUR(1000)));
            env(trust(cheri, gwEUR(1000)));
            env.close();
            env(pay(gw, becky, gwAUD(500)));
            env(pay(gw, becky, gwCAD(500)));
            env(pay(gw, becky, gwEUR(500)));
            env(pay(gw, cheri, gwAUD(500)));
            env(pay(gw, cheri, gwCAD(500)));
            env.close();
 
            // An nft without flagCreateTrustLines but with a non-zero transfer
            // fee will not allow creating offers that use IOUs for payment.
            for (std::uint32_t const xferFee : {0, 1})
            {
                uint256 const nftNoAutoTrustID{
                    token::getNextID(env, alice, 0u, tfTransferable, xferFee)};
                env(token::mint(alice, 0u), token::xferFee(xferFee), txflags(tfTransferable));
                env.close();
 
                // becky buys the nft for 1 drop.
                uint256 const beckyBuyOfferIndex = keylet::nftoffer(becky, env.seq(becky)).key;
                env(token::createOffer(becky, nftNoAutoTrustID, drops(1)), token::owner(alice));
                env.close();
                env(token::acceptBuyOffer(alice, beckyBuyOfferIndex));
                env.close();
 
                // becky attempts to sell the nft for AUD.
                TER const createOfferTER = (xferFee != 0u) ? TER(tecNO_LINE) : TER(tesSUCCESS);
                uint256 const beckyOfferIndex = keylet::nftoffer(becky, env.seq(becky)).key;
                env(token::createOffer(becky, nftNoAutoTrustID, gwAUD(100)),
                    txflags(tfSellNFToken),
                    ter(createOfferTER));
                env.close();
 
                // cheri offers to buy the nft for CAD.
                uint256 const cheriOfferIndex = keylet::nftoffer(cheri, env.seq(cheri)).key;
                env(token::createOffer(cheri, nftNoAutoTrustID, gwCAD(100)),
                    token::owner(becky),
                    ter(createOfferTER));
                env.close();
 
                // To keep things tidy, cancel the offers.
                env(token::cancelOffer(becky, {beckyOfferIndex}));
                env(token::cancelOffer(cheri, {cheriOfferIndex}));
                env.close();
            }
            // An nft with flagCreateTrustLines but with a non-zero transfer
            // fee allows transfers using IOUs for payment.
            {
                std::uint16_t const transferFee = 10000;  // 10%
 
                uint256 const nftAutoTrustID{
                    token::getNextID(env, alice, 0u, tfTransferable | tfTrustLine, transferFee)};
 
                // If the fixRemoveNFTokenAutoTrustLine amendment is active
                // then this transaction fails.
                {
                    TER const mintTER = tweakedFeatures[fixRemoveNFTokenAutoTrustLine]
                        ? static_cast<TER>(temINVALID_FLAG)
                        : static_cast<TER>(tesSUCCESS);
 
                    env(token::mint(alice, 0u),
                        token::xferFee(transferFee),
                        txflags(tfTransferable | tfTrustLine),
                        ter(mintTER));
                    env.close();
 
                    // If fixRemoveNFTokenAutoTrustLine is active the rest
                    // of this test falls on its face.
                    if (tweakedFeatures[fixRemoveNFTokenAutoTrustLine])
                        break;
                }
                // becky buys the nft for 1 drop.
                uint256 const beckyBuyOfferIndex = keylet::nftoffer(becky, env.seq(becky)).key;
                env(token::createOffer(becky, nftAutoTrustID, drops(1)), token::owner(alice));
                env.close();
                env(token::acceptBuyOffer(alice, beckyBuyOfferIndex));
                env.close();
 
                // becky sells the nft for AUD.
                uint256 const beckySellOfferIndex = keylet::nftoffer(becky, env.seq(becky)).key;
                env(token::createOffer(becky, nftAutoTrustID, gwAUD(100)), txflags(tfSellNFToken));
                env.close();
                env(token::acceptSellOffer(cheri, beckySellOfferIndex));
                env.close();
 
                // alice should now have a trust line for gwAUD.
                BEAST_EXPECT(env.balance(alice, gwAUD) == gwAUD(10));
 
                // becky buys the nft back for CAD.
                uint256 const beckyBuyBackOfferIndex = keylet::nftoffer(becky, env.seq(becky)).key;
                env(token::createOffer(becky, nftAutoTrustID, gwCAD(50)), token::owner(cheri));
                env.close();
                env(token::acceptBuyOffer(cheri, beckyBuyBackOfferIndex));
                env.close();
 
                // alice should now have a trust line for gwAUD and gwCAD.
                BEAST_EXPECT(env.balance(alice, gwAUD) == gwAUD(10));
                BEAST_EXPECT(env.balance(alice, gwCAD) == gwCAD(5));
            }
            // Now that alice has trust lines preestablished, an nft without
            // flagCreateTrustLines will work for preestablished trust lines.
            {
                std::uint16_t const transferFee = 5000;  // 5%
                uint256 const nftNoAutoTrustID{
                    token::getNextID(env, alice, 0u, tfTransferable, transferFee)};
                env(token::mint(alice, 0u), token::xferFee(transferFee), txflags(tfTransferable));
                env.close();
 
                // alice sells the nft using AUD.
                uint256 const aliceSellOfferIndex = keylet::nftoffer(alice, env.seq(alice)).key;
                env(token::createOffer(alice, nftNoAutoTrustID, gwAUD(200)),
                    txflags(tfSellNFToken));
                env.close();
                env(token::acceptSellOffer(cheri, aliceSellOfferIndex));
                env.close();
 
                // alice should now have AUD(210):
                //  o 200 for this sale and
                //  o 10 for the previous sale's fee.
                BEAST_EXPECT(env.balance(alice, gwAUD) == gwAUD(210));
 
                // cheri can't sell the NFT for EUR, but can for CAD.
                env(token::createOffer(cheri, nftNoAutoTrustID, gwEUR(50)),
                    txflags(tfSellNFToken),
                    ter(tecNO_LINE));
                env.close();
                uint256 const cheriSellOfferIndex = keylet::nftoffer(cheri, env.seq(cheri)).key;
                env(token::createOffer(cheri, nftNoAutoTrustID, gwCAD(100)),
                    txflags(tfSellNFToken));
                env.close();
                env(token::acceptSellOffer(becky, cheriSellOfferIndex));
                env.close();
 
                // alice should now have CAD(10):
                //  o 5 from this sale's fee and
                //  o 5 for the previous sale's fee.
                BEAST_EXPECT(env.balance(alice, gwCAD) == gwCAD(10));
            }
        }
    }
 
    void
    testMintFlagTransferable(FeatureBitset features)
    {
        // Exercise NFTs with flagTransferable set and not set.
        testcase("Mint flagTransferable");
 
        using namespace test::jtx;
 
        Env env{*this, features};
 
        Account const alice{"alice"};
        Account const becky{"becky"};
        Account const minter{"minter"};
 
        env.fund(XRP(1000), alice, becky, minter);
        env.close();
 
        // First try an nft made by alice without flagTransferable set.
        {
            BEAST_EXPECT(ownerCount(env, alice) == 0);
            uint256 const nftAliceNoTransferID{token::getNextID(env, alice, 0u)};
            env(token::mint(alice, 0u), token::xferFee(0));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 1);
 
            // becky tries to offer to buy alice's nft.
            BEAST_EXPECT(ownerCount(env, becky) == 0);
            env(token::createOffer(becky, nftAliceNoTransferID, XRP(20)),
                token::owner(alice),
                ter(tefNFTOKEN_IS_NOT_TRANSFERABLE));
 
            // alice offers to sell the nft and becky accepts the offer.
            uint256 const aliceSellOfferIndex = keylet::nftoffer(alice, env.seq(alice)).key;
            env(token::createOffer(alice, nftAliceNoTransferID, XRP(20)), txflags(tfSellNFToken));
            env.close();
            env(token::acceptSellOffer(becky, aliceSellOfferIndex));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 0);
            BEAST_EXPECT(ownerCount(env, becky) == 1);
 
            // becky tries to offer the nft for sale.
            env(token::createOffer(becky, nftAliceNoTransferID, XRP(21)),
                txflags(tfSellNFToken),
                ter(tefNFTOKEN_IS_NOT_TRANSFERABLE));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 0);
            BEAST_EXPECT(ownerCount(env, becky) == 1);
 
            // becky tries to offer the nft for sale with alice as the
            // destination.  That also doesn't work.
            env(token::createOffer(becky, nftAliceNoTransferID, XRP(21)),
                txflags(tfSellNFToken),
                token::destination(alice),
                ter(tefNFTOKEN_IS_NOT_TRANSFERABLE));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 0);
            BEAST_EXPECT(ownerCount(env, becky) == 1);
 
            // alice offers to buy the nft back from becky.  becky accepts
            // the offer.
            uint256 const aliceBuyOfferIndex = keylet::nftoffer(alice, env.seq(alice)).key;
            env(token::createOffer(alice, nftAliceNoTransferID, XRP(22)), token::owner(becky));
            env.close();
            env(token::acceptBuyOffer(becky, aliceBuyOfferIndex));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 1);
            BEAST_EXPECT(ownerCount(env, becky) == 0);
 
            // alice burns her nft so accounting is simpler below.
            env(token::burn(alice, nftAliceNoTransferID));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 0);
            BEAST_EXPECT(ownerCount(env, becky) == 0);
        }
        // Try an nft minted by minter for alice without flagTransferable set.
        {
            env(token::setMinter(alice, minter));
            env.close();
 
            BEAST_EXPECT(ownerCount(env, minter) == 0);
            uint256 const nftMinterNoTransferID{token::getNextID(env, alice, 0u)};
            env(token::mint(minter), token::issuer(alice));
            env.close();
            BEAST_EXPECT(ownerCount(env, minter) == 1);
 
            // becky tries to offer to buy minter's nft.
            BEAST_EXPECT(ownerCount(env, becky) == 0);
            env(token::createOffer(becky, nftMinterNoTransferID, XRP(20)),
                token::owner(minter),
                ter(tefNFTOKEN_IS_NOT_TRANSFERABLE));
            env.close();
            BEAST_EXPECT(ownerCount(env, becky) == 0);
 
            // alice removes authorization of minter.
            env(token::clearMinter(alice));
            env.close();
 
            // minter tries to offer their nft for sale.
            BEAST_EXPECT(ownerCount(env, minter) == 1);
            env(token::createOffer(minter, nftMinterNoTransferID, XRP(21)),
                txflags(tfSellNFToken),
                ter(tefNFTOKEN_IS_NOT_TRANSFERABLE));
            env.close();
            BEAST_EXPECT(ownerCount(env, minter) == 1);
 
            // Let enough ledgers pass that old transactions are no longer
            // retried, then alice gives authorization back to minter.
            for (int i = 0; i < 10; ++i)
                env.close();
 
            env(token::setMinter(alice, minter));
            env.close();
            BEAST_EXPECT(ownerCount(env, minter) == 1);
 
            // minter successfully offers their nft for sale.
            BEAST_EXPECT(ownerCount(env, minter) == 1);
            uint256 const minterSellOfferIndex = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftMinterNoTransferID, XRP(22)), txflags(tfSellNFToken));
            env.close();
            BEAST_EXPECT(ownerCount(env, minter) == 2);
 
            // alice removes authorization of minter so we can see whether
            // minter's pre-existing offer still works.
            env(token::clearMinter(alice));
            env.close();
 
            // becky buys minter's nft even though minter is no longer alice's
            // official minter.
            BEAST_EXPECT(ownerCount(env, becky) == 0);
            env(token::acceptSellOffer(becky, minterSellOfferIndex));
            env.close();
            BEAST_EXPECT(ownerCount(env, becky) == 1);
            BEAST_EXPECT(ownerCount(env, minter) == 0);
 
            // becky attempts to sell the nft.
            env(token::createOffer(becky, nftMinterNoTransferID, XRP(23)),
                txflags(tfSellNFToken),
                ter(tefNFTOKEN_IS_NOT_TRANSFERABLE));
            env.close();
 
            // Since minter is not, at the moment, alice's official minter
            // they cannot create an offer to buy the nft they minted.
            BEAST_EXPECT(ownerCount(env, minter) == 0);
            env(token::createOffer(minter, nftMinterNoTransferID, XRP(24)),
                token::owner(becky),
                ter(tefNFTOKEN_IS_NOT_TRANSFERABLE));
            env.close();
            BEAST_EXPECT(ownerCount(env, minter) == 0);
 
            // alice can create an offer to buy the nft.
            BEAST_EXPECT(ownerCount(env, alice) == 0);
            uint256 const aliceBuyOfferIndex = keylet::nftoffer(alice, env.seq(alice)).key;
            env(token::createOffer(alice, nftMinterNoTransferID, XRP(25)), token::owner(becky));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 1);
 
            // Let enough ledgers pass that old transactions are no longer
            // retried, then alice gives authorization back to minter.
            for (int i = 0; i < 10; ++i)
                env.close();
 
            env(token::setMinter(alice, minter));
            env.close();
 
            // Now minter can create an offer to buy the nft.
            BEAST_EXPECT(ownerCount(env, minter) == 0);
            uint256 const minterBuyOfferIndex = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftMinterNoTransferID, XRP(26)), token::owner(becky));
            env.close();
            BEAST_EXPECT(ownerCount(env, minter) == 1);
 
            // alice removes authorization of minter so we can see whether
            // minter's pre-existing buy offer still works.
            env(token::clearMinter(alice));
            env.close();
 
            // becky accepts minter's sell offer.
            BEAST_EXPECT(ownerCount(env, minter) == 1);
            BEAST_EXPECT(ownerCount(env, becky) == 1);
            env(token::acceptBuyOffer(becky, minterBuyOfferIndex));
            env.close();
            BEAST_EXPECT(ownerCount(env, minter) == 1);
            BEAST_EXPECT(ownerCount(env, becky) == 0);
            BEAST_EXPECT(ownerCount(env, alice) == 1);
 
            // minter burns their nft and alice cancels her offer so the
            // next tests can start with a clean slate.
            env(token::burn(minter, nftMinterNoTransferID), ter(tesSUCCESS));
            env.close();
            env(token::cancelOffer(alice, {aliceBuyOfferIndex}));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 0);
            BEAST_EXPECT(ownerCount(env, becky) == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 0);
        }
        // nfts with flagTransferable set should be buyable and salable
        // by anybody.
        {
            BEAST_EXPECT(ownerCount(env, alice) == 0);
            uint256 const nftAliceID{token::getNextID(env, alice, 0u, tfTransferable)};
            env(token::mint(alice, 0u), txflags(tfTransferable));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 1);
 
            // Both alice and becky can make offers for alice's nft.
            uint256 const aliceSellOfferIndex = keylet::nftoffer(alice, env.seq(alice)).key;
            env(token::createOffer(alice, nftAliceID, XRP(20)), txflags(tfSellNFToken));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 2);
 
            uint256 const beckyBuyOfferIndex = keylet::nftoffer(becky, env.seq(becky)).key;
            env(token::createOffer(becky, nftAliceID, XRP(21)), token::owner(alice));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 2);
 
            // becky accepts alice's sell offer.
            env(token::acceptSellOffer(becky, aliceSellOfferIndex));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 0);
            BEAST_EXPECT(ownerCount(env, becky) == 2);
 
            // becky offers to sell the nft.
            uint256 const beckySellOfferIndex = keylet::nftoffer(becky, env.seq(becky)).key;
            env(token::createOffer(becky, nftAliceID, XRP(22)), txflags(tfSellNFToken));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 0);
            BEAST_EXPECT(ownerCount(env, becky) == 3);
 
            // minter buys the nft (even though minter is not currently
            // alice's minter).
            env(token::acceptSellOffer(minter, beckySellOfferIndex));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 0);
            BEAST_EXPECT(ownerCount(env, becky) == 1);
            BEAST_EXPECT(ownerCount(env, minter) == 1);
 
            // minter offers to sell the nft.
            uint256 const minterSellOfferIndex = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftAliceID, XRP(23)), txflags(tfSellNFToken));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 0);
            BEAST_EXPECT(ownerCount(env, becky) == 1);
            BEAST_EXPECT(ownerCount(env, minter) == 2);
 
            // alice buys back the nft.
            env(token::acceptSellOffer(alice, minterSellOfferIndex));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 1);
            BEAST_EXPECT(ownerCount(env, becky) == 1);
            BEAST_EXPECT(ownerCount(env, minter) == 0);
 
            // Remember the buy offer that becky made for alice's token way
            // back when?  It's still in the ledger, and alice accepts it.
            env(token::acceptBuyOffer(alice, beckyBuyOfferIndex));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 0);
            BEAST_EXPECT(ownerCount(env, becky) == 1);
            BEAST_EXPECT(ownerCount(env, minter) == 0);
 
            // Just for tidiness, becky burns the token before shutting
            // things down.
            env(token::burn(becky, nftAliceID));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 0);
            BEAST_EXPECT(ownerCount(env, becky) == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 0);
        }
    }
 
    void
    testMintTransferFee(FeatureBitset features)
    {
        // Exercise NFTs with and without a transferFee.
        testcase("Mint transferFee");
 
        using namespace test::jtx;
 
        Env env{*this, features};
        auto const baseFee = env.current()->fees().base;
 
        Account const alice{"alice"};
        Account const becky{"becky"};
        Account const carol{"carol"};
        Account const minter{"minter"};
        Account const gw{"gw"};
        IOU const gwXAU(gw["XAU"]);
 
        env.fund(XRP(1000), alice, becky, carol, minter, gw);
        env.close();
 
        env(trust(alice, gwXAU(2000)));
        env(trust(becky, gwXAU(2000)));
        env(trust(carol, gwXAU(2000)));
        env(trust(minter, gwXAU(2000)));
        env.close();
        env(pay(gw, alice, gwXAU(1000)));
        env(pay(gw, becky, gwXAU(1000)));
        env(pay(gw, carol, gwXAU(1000)));
        env(pay(gw, minter, gwXAU(1000)));
        env.close();
 
        // Giving alice a minter helps us see if transfer rates are affected
        // by that.
        env(token::setMinter(alice, minter));
        env.close();
 
        // If there is no transferFee, then alice gets nothing for the
        // transfer.
        {
            BEAST_EXPECT(ownerCount(env, alice) == 1);
            BEAST_EXPECT(ownerCount(env, becky) == 1);
            BEAST_EXPECT(ownerCount(env, carol) == 1);
            BEAST_EXPECT(ownerCount(env, minter) == 1);
 
            uint256 const nftID = token::getNextID(env, alice, 0u, tfTransferable);
            env(token::mint(alice), txflags(tfTransferable));
            env.close();
 
            // Becky buys the nft for XAU(10).  Check balances.
            uint256 const beckyBuyOfferIndex = keylet::nftoffer(becky, env.seq(becky)).key;
            env(token::createOffer(becky, nftID, gwXAU(10)), token::owner(alice));
            env.close();
            BEAST_EXPECT(env.balance(alice, gwXAU) == gwXAU(1000));
            BEAST_EXPECT(env.balance(becky, gwXAU) == gwXAU(1000));
 
            env(token::acceptBuyOffer(alice, beckyBuyOfferIndex));
            env.close();
            BEAST_EXPECT(env.balance(alice, gwXAU) == gwXAU(1010));
            BEAST_EXPECT(env.balance(becky, gwXAU) == gwXAU(990));
 
            // becky sells nft to carol.  alice's balance should not change.
            uint256 const beckySellOfferIndex = keylet::nftoffer(becky, env.seq(becky)).key;
            env(token::createOffer(becky, nftID, gwXAU(10)), txflags(tfSellNFToken));
            env.close();
            env(token::acceptSellOffer(carol, beckySellOfferIndex));
            env.close();
            BEAST_EXPECT(env.balance(alice, gwXAU) == gwXAU(1010));
            BEAST_EXPECT(env.balance(becky, gwXAU) == gwXAU(1000));
            BEAST_EXPECT(env.balance(carol, gwXAU) == gwXAU(990));
 
            // minter buys nft from carol.  alice's balance should not change.
            uint256 const minterBuyOfferIndex = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftID, gwXAU(10)), token::owner(carol));
            env.close();
            env(token::acceptBuyOffer(carol, minterBuyOfferIndex));
            env.close();
            BEAST_EXPECT(env.balance(alice, gwXAU) == gwXAU(1010));
            BEAST_EXPECT(env.balance(becky, gwXAU) == gwXAU(1000));
            BEAST_EXPECT(env.balance(carol, gwXAU) == gwXAU(1000));
            BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(990));
 
            // minter sells the nft to alice.  gwXAU balances should finish
            // where they started.
            uint256 const minterSellOfferIndex = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftID, gwXAU(10)), txflags(tfSellNFToken));
            env.close();
            env(token::acceptSellOffer(alice, minterSellOfferIndex));
            env.close();
            BEAST_EXPECT(env.balance(alice, gwXAU) == gwXAU(1000));
            BEAST_EXPECT(env.balance(becky, gwXAU) == gwXAU(1000));
            BEAST_EXPECT(env.balance(carol, gwXAU) == gwXAU(1000));
            BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(1000));
 
            // alice burns the nft to make later tests easier to think about.
            env(token::burn(alice, nftID));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 1);
            BEAST_EXPECT(ownerCount(env, becky) == 1);
            BEAST_EXPECT(ownerCount(env, carol) == 1);
            BEAST_EXPECT(ownerCount(env, minter) == 1);
        }
 
        // Set the smallest possible transfer fee.
        {
            // An nft with a transfer fee of 1 basis point.
            uint256 const nftID = token::getNextID(env, alice, 0u, tfTransferable, 1);
            env(token::mint(alice), txflags(tfTransferable), token::xferFee(1));
            env.close();
 
            // Becky buys the nft for XAU(10).  Check balances.
            uint256 const beckyBuyOfferIndex = keylet::nftoffer(becky, env.seq(becky)).key;
            env(token::createOffer(becky, nftID, gwXAU(10)), token::owner(alice));
            env.close();
            BEAST_EXPECT(env.balance(alice, gwXAU) == gwXAU(1000));
            BEAST_EXPECT(env.balance(becky, gwXAU) == gwXAU(1000));
 
            env(token::acceptBuyOffer(alice, beckyBuyOfferIndex));
            env.close();
            BEAST_EXPECT(env.balance(alice, gwXAU) == gwXAU(1010));
            BEAST_EXPECT(env.balance(becky, gwXAU) == gwXAU(990));
 
            // becky sells nft to carol.  alice's balance goes up.
            uint256 const beckySellOfferIndex = keylet::nftoffer(becky, env.seq(becky)).key;
            env(token::createOffer(becky, nftID, gwXAU(10)), txflags(tfSellNFToken));
            env.close();
            env(token::acceptSellOffer(carol, beckySellOfferIndex));
            env.close();
 
            BEAST_EXPECT(env.balance(alice, gwXAU) == gwXAU(1010.0001));
            BEAST_EXPECT(env.balance(becky, gwXAU) == gwXAU(999.9999));
            BEAST_EXPECT(env.balance(carol, gwXAU) == gwXAU(990));
 
            // minter buys nft from carol.  alice's balance goes up.
            uint256 const minterBuyOfferIndex = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftID, gwXAU(10)), token::owner(carol));
            env.close();
            env(token::acceptBuyOffer(carol, minterBuyOfferIndex));
            env.close();
 
            BEAST_EXPECT(env.balance(alice, gwXAU) == gwXAU(1010.0002));
            BEAST_EXPECT(env.balance(becky, gwXAU) == gwXAU(999.9999));
            BEAST_EXPECT(env.balance(carol, gwXAU) == gwXAU(999.9999));
            BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(990));
 
            // minter sells the nft to alice.  Because alice is part of the
            // transaction no transfer fee is removed.
            uint256 const minterSellOfferIndex = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftID, gwXAU(10)), txflags(tfSellNFToken));
            env.close();
            env(token::acceptSellOffer(alice, minterSellOfferIndex));
            env.close();
            BEAST_EXPECT(env.balance(alice, gwXAU) == gwXAU(1000.0002));
            BEAST_EXPECT(env.balance(becky, gwXAU) == gwXAU(999.9999));
            BEAST_EXPECT(env.balance(carol, gwXAU) == gwXAU(999.9999));
            BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(1000));
 
            // alice pays to becky and carol so subsequent tests are easier
            // to think about.
            env(pay(alice, becky, gwXAU(0.0001)));
            env(pay(alice, carol, gwXAU(0.0001)));
            env.close();
 
            BEAST_EXPECT(env.balance(alice, gwXAU) == gwXAU(1000));
            BEAST_EXPECT(env.balance(becky, gwXAU) == gwXAU(1000));
            BEAST_EXPECT(env.balance(carol, gwXAU) == gwXAU(1000));
            BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(1000));
 
            // alice burns the nft to make later tests easier to think about.
            env(token::burn(alice, nftID));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 1);
            BEAST_EXPECT(ownerCount(env, becky) == 1);
            BEAST_EXPECT(ownerCount(env, carol) == 1);
            BEAST_EXPECT(ownerCount(env, minter) == 1);
        }
 
        // Set the largest allowed transfer fee.
        {
            // A transfer fee greater than 50% is not allowed.
            env(token::mint(alice),
                txflags(tfTransferable),
                token::xferFee(maxTransferFee + 1),
                ter(temBAD_NFTOKEN_TRANSFER_FEE));
            env.close();
 
            // Make an nft with a transfer fee of 50%.
            uint256 const nftID = token::getNextID(env, alice, 0u, tfTransferable, maxTransferFee);
            env(token::mint(alice), txflags(tfTransferable), token::xferFee(maxTransferFee));
            env.close();
 
            // Becky buys the nft for XAU(10).  Check balances.
            uint256 const beckyBuyOfferIndex = keylet::nftoffer(becky, env.seq(becky)).key;
            env(token::createOffer(becky, nftID, gwXAU(10)), token::owner(alice));
            env.close();
            BEAST_EXPECT(env.balance(alice, gwXAU) == gwXAU(1000));
            BEAST_EXPECT(env.balance(becky, gwXAU) == gwXAU(1000));
 
            env(token::acceptBuyOffer(alice, beckyBuyOfferIndex));
            env.close();
            BEAST_EXPECT(env.balance(alice, gwXAU) == gwXAU(1010));
            BEAST_EXPECT(env.balance(becky, gwXAU) == gwXAU(990));
 
            // becky sells nft to minter.  alice's balance goes up.
            uint256 const beckySellOfferIndex = keylet::nftoffer(becky, env.seq(becky)).key;
            env(token::createOffer(becky, nftID, gwXAU(100)), txflags(tfSellNFToken));
            env.close();
            env(token::acceptSellOffer(minter, beckySellOfferIndex));
            env.close();
 
            BEAST_EXPECT(env.balance(alice, gwXAU) == gwXAU(1060));
            BEAST_EXPECT(env.balance(becky, gwXAU) == gwXAU(1040));
            BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(900));
 
            // carol buys nft from minter.  alice's balance goes up.
            uint256 const carolBuyOfferIndex = keylet::nftoffer(carol, env.seq(carol)).key;
            env(token::createOffer(carol, nftID, gwXAU(10)), token::owner(minter));
            env.close();
            env(token::acceptBuyOffer(minter, carolBuyOfferIndex));
            env.close();
 
            BEAST_EXPECT(env.balance(alice, gwXAU) == gwXAU(1065));
            BEAST_EXPECT(env.balance(becky, gwXAU) == gwXAU(1040));
            BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(905));
            BEAST_EXPECT(env.balance(carol, gwXAU) == gwXAU(990));
 
            // carol sells the nft to alice.  Because alice is part of the
            // transaction no transfer fee is removed.
            uint256 const carolSellOfferIndex = keylet::nftoffer(carol, env.seq(carol)).key;
            env(token::createOffer(carol, nftID, gwXAU(10)), txflags(tfSellNFToken));
            env.close();
            env(token::acceptSellOffer(alice, carolSellOfferIndex));
            env.close();
 
            BEAST_EXPECT(env.balance(alice, gwXAU) == gwXAU(1055));
            BEAST_EXPECT(env.balance(becky, gwXAU) == gwXAU(1040));
            BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(905));
            BEAST_EXPECT(env.balance(carol, gwXAU) == gwXAU(1000));
 
            // rebalance so subsequent tests are easier to think about.
            env(pay(alice, minter, gwXAU(55)));
            env(pay(becky, minter, gwXAU(40)));
            env.close();
            BEAST_EXPECT(env.balance(alice, gwXAU) == gwXAU(1000));
            BEAST_EXPECT(env.balance(becky, gwXAU) == gwXAU(1000));
            BEAST_EXPECT(env.balance(carol, gwXAU) == gwXAU(1000));
            BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(1000));
 
            // alice burns the nft to make later tests easier to think about.
            env(token::burn(alice, nftID));
            env.close();
            BEAST_EXPECT(ownerCount(env, alice) == 1);
            BEAST_EXPECT(ownerCount(env, becky) == 1);
            BEAST_EXPECT(ownerCount(env, carol) == 1);
            BEAST_EXPECT(ownerCount(env, minter) == 1);
        }
 
        // See the impact of rounding when the nft is sold for small amounts
        // of drops.
        for (auto NumberSwitchOver : {true})
        {
            if (NumberSwitchOver)
            {
                env.enableFeature(fixUniversalNumber);
            }
            else
            {
                env.disableFeature(fixUniversalNumber);
            }
 
            // An nft with a transfer fee of 1 basis point.
            uint256 const nftID = token::getNextID(env, alice, 0u, tfTransferable, 1);
            env(token::mint(alice), txflags(tfTransferable), token::xferFee(1));
            env.close();
 
            // minter buys the nft for XRP(1).  Since the transfer involves
            // alice there should be no transfer fee.
            STAmount aliceBalance = env.balance(alice);
            STAmount minterBalance = env.balance(minter);
            uint256 const minterBuyOfferIndex = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftID, XRP(1)), token::owner(alice));
            env.close();
            env(token::acceptBuyOffer(alice, minterBuyOfferIndex));
            env.close();
            aliceBalance += XRP(1) - baseFee;
            minterBalance -= XRP(1) + baseFee;
            BEAST_EXPECT(env.balance(alice) == aliceBalance);
            BEAST_EXPECT(env.balance(minter) == minterBalance);
 
            // minter sells to carol.  The payment is just small enough that
            // alice does not get any transfer fee.
            auto pmt = NumberSwitchOver ? drops(50000) : drops(99999);
            STAmount carolBalance = env.balance(carol);
            uint256 const minterSellOfferIndex = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftID, pmt), txflags(tfSellNFToken));
            env.close();
            env(token::acceptSellOffer(carol, minterSellOfferIndex));
            env.close();
            minterBalance += pmt - baseFee;
            carolBalance -= pmt + baseFee;
            BEAST_EXPECT(env.balance(alice) == aliceBalance);
            BEAST_EXPECT(env.balance(minter) == minterBalance);
            BEAST_EXPECT(env.balance(carol) == carolBalance);
 
            // carol sells to becky. This is the smallest amount to pay for a
            // transfer that enables a transfer fee of 1 basis point.
            STAmount beckyBalance = env.balance(becky);
            uint256 const beckyBuyOfferIndex = keylet::nftoffer(becky, env.seq(becky)).key;
            pmt = NumberSwitchOver ? drops(50001) : drops(100000);
            env(token::createOffer(becky, nftID, pmt), token::owner(carol));
            env.close();
            env(token::acceptBuyOffer(carol, beckyBuyOfferIndex));
            env.close();
            carolBalance += pmt - drops(1) - baseFee;
            beckyBalance -= pmt + baseFee;
            aliceBalance += drops(1);
 
            BEAST_EXPECT(env.balance(alice) == aliceBalance);
            BEAST_EXPECT(env.balance(minter) == minterBalance);
            BEAST_EXPECT(env.balance(carol) == carolBalance);
            BEAST_EXPECT(env.balance(becky) == beckyBalance);
        }
 
        // See the impact of rounding when the nft is sold for small amounts
        // of an IOU.
        {
            // An nft with a transfer fee of 1 basis point.
            uint256 const nftID = token::getNextID(env, alice, 0u, tfTransferable, 1);
            env(token::mint(alice), txflags(tfTransferable), token::xferFee(1));
            env.close();
 
            // Due to the floating point nature of IOUs we need to
            // significantly reduce the gwXAU balances of our accounts prior
            // to the iou transfer.  Otherwise no transfers will happen.
            env(pay(alice, gw, env.balance(alice, gwXAU)));
            env(pay(minter, gw, env.balance(minter, gwXAU)));
            env(pay(becky, gw, env.balance(becky, gwXAU)));
            env.close();
 
            STAmount const startXAUBalance(
                gwXAU.issue(), STAmount::cMinValue, STAmount::cMinOffset + 5);
            env(pay(gw, alice, startXAUBalance));
            env(pay(gw, minter, startXAUBalance));
            env(pay(gw, becky, startXAUBalance));
            env.close();
 
            // Here is the smallest expressible gwXAU amount.
            STAmount const tinyXAU(gwXAU.issue(), STAmount::cMinValue, STAmount::cMinOffset);
 
            // minter buys the nft for tinyXAU.  Since the transfer involves
            // alice there should be no transfer fee.
            STAmount aliceBalance = env.balance(alice, gwXAU);
            STAmount minterBalance = env.balance(minter, gwXAU);
            uint256 const minterBuyOfferIndex = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftID, tinyXAU), token::owner(alice));
            env.close();
            env(token::acceptBuyOffer(alice, minterBuyOfferIndex));
            env.close();
            aliceBalance += tinyXAU;
            minterBalance -= tinyXAU;
            BEAST_EXPECT(env.balance(alice, gwXAU) == aliceBalance);
            BEAST_EXPECT(env.balance(minter, gwXAU) == minterBalance);
 
            // minter sells to carol.
            STAmount carolBalance = env.balance(carol, gwXAU);
            uint256 const minterSellOfferIndex = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftID, tinyXAU), txflags(tfSellNFToken));
            env.close();
            env(token::acceptSellOffer(carol, minterSellOfferIndex));
            env.close();
 
            minterBalance += tinyXAU;
            carolBalance -= tinyXAU;
            // tiny XAU is so small that alice does not get a transfer fee.
            BEAST_EXPECT(env.balance(alice, gwXAU) == aliceBalance);
            BEAST_EXPECT(env.balance(minter, gwXAU) == minterBalance);
            BEAST_EXPECT(env.balance(carol, gwXAU) == carolBalance);
 
            // carol sells to becky.  This is the smallest gwXAU amount
            // to pay for a transfer that enables a transfer fee of 1.
            STAmount const cheapNFT(gwXAU.issue(), STAmount::cMinValue, STAmount::cMinOffset + 5);
 
            STAmount beckyBalance = env.balance(becky, gwXAU);
            uint256 const beckyBuyOfferIndex = keylet::nftoffer(becky, env.seq(becky)).key;
            env(token::createOffer(becky, nftID, cheapNFT), token::owner(carol));
            env.close();
            env(token::acceptBuyOffer(carol, beckyBuyOfferIndex));
            env.close();
 
            aliceBalance += tinyXAU;
            beckyBalance -= cheapNFT;
            carolBalance += cheapNFT - tinyXAU;
            BEAST_EXPECT(env.balance(alice, gwXAU) == aliceBalance);
            BEAST_EXPECT(env.balance(minter, gwXAU) == minterBalance);
            BEAST_EXPECT(env.balance(carol, gwXAU) == carolBalance);
            BEAST_EXPECT(env.balance(becky, gwXAU) == beckyBalance);
        }
    }
 
    void
    testMintTaxon(FeatureBitset features)
    {
        // Exercise the NFT taxon field.
        testcase("Mint taxon");
 
        using namespace test::jtx;
 
        Env env{*this, features};
 
        Account const alice{"alice"};
        Account const becky{"becky"};
 
        env.fund(XRP(1000), alice, becky);
        env.close();
 
        // The taxon field is incorporated straight into the NFT ID.  So
        // tests only need to operate on NFT IDs; we don't need to generate
        // any transactions.
 
        // The taxon value should be recoverable from the NFT ID.
        {
            uint256 const nftID = token::getNextID(env, alice, 0u);
            BEAST_EXPECT(nft::getTaxon(nftID) == nft::toTaxon(0));
        }
 
        // Make sure the full range of taxon values work.  We just tried
        // the minimum.  Now try the largest.
        {
            uint256 const nftID = token::getNextID(env, alice, 0xFFFFFFFFu);
            BEAST_EXPECT(nft::getTaxon(nftID) == nft::toTaxon((0xFFFFFFFF)));
        }
 
        // Do some touch testing to show that the taxon is recoverable no
        // matter what else changes around it in the nft ID.
        {
            std::uint32_t const taxon = rand_int<std::uint32_t>();
            for (int i = 0; i < 10; ++i)
            {
                // lambda to produce a useful message on error.
                auto check = [this](std::uint32_t taxon, uint256 const& nftID) {
                    nft::Taxon const gotTaxon = nft::getTaxon(nftID);
                    if (nft::toTaxon(taxon) == gotTaxon)
                    {
                        pass();
                    }
                    else
                    {
                        std::stringstream ss;
                        ss << "Taxon recovery failed from nftID " << to_string(nftID)
                           << ".  Expected: " << taxon << "; got: " << gotTaxon;
                        fail(ss.str());
                    }
                };
 
                uint256 const nftAliceID = token::getID(
                    env,
                    alice,
                    taxon,
                    rand_int<std::uint32_t>(),
                    rand_int<std::uint16_t>(),
                    rand_int<std::uint16_t>());
                check(taxon, nftAliceID);
 
                uint256 const nftBeckyID = token::getID(
                    env,
                    becky,
                    taxon,
                    rand_int<std::uint32_t>(),
                    rand_int<std::uint16_t>(),
                    rand_int<std::uint16_t>());
                check(taxon, nftBeckyID);
            }
        }
    }
 
    void
    testMintURI(FeatureBitset features)
    {
        // Exercise the NFT URI field.
        //  1. Create a number of NFTs with and without URIs.
        //  2. Retrieve the NFTs from the server.
        //  3. Make sure the right URI is attached to each NFT.
        testcase("Mint URI");
 
        using namespace test::jtx;
 
        Env env{*this, features};
 
        Account const alice{"alice"};
        Account const becky{"becky"};
 
        env.fund(XRP(10000), alice, becky);
        env.close();
 
        // lambda that returns a randomly generated string which fits
        // the constraints of a URI.  Empty strings may be returned.
        // In the empty string case do not add the URI to the nft.
        auto randURI = []() {
            std::string ret;
 
            // About 20% of the returned strings should be empty
            if (rand_int(4) == 0)
                return ret;
 
            std::size_t const strLen = rand_int(256);
            ret.reserve(strLen);
            for (std::size_t i = 0; i < strLen; ++i)
                ret.push_back(rand_byte());
 
            return ret;
        };
 
        // Make a list of URIs that we'll put in nfts.
        struct Entry
        {
            std::string uri;
            std::uint32_t taxon;
 
            Entry(std::string uri_, std::uint32_t taxon_) : uri(std::move(uri_)), taxon(taxon_)
            {
            }
        };
 
        std::vector<Entry> entries;
        entries.reserve(100);
        for (std::size_t i = 0; i < 100; ++i)
            entries.emplace_back(randURI(), rand_int<std::uint32_t>());
 
        // alice creates nfts using entries.
        for (Entry const& entry : entries)
        {
            if (entry.uri.empty())
            {
                env(token::mint(alice, entry.taxon));
            }
            else
            {
                env(token::mint(alice, entry.taxon), token::uri(entry.uri));
            }
            env.close();
        }
 
        // Recover alice's nfts from the ledger.
        Json::Value aliceNFTs = [&env, &alice]() {
            Json::Value params;
            params[jss::account] = alice.human();
            params[jss::type] = "state";
            return env.rpc("json", "account_nfts", to_string(params));
        }();
 
        // Verify that the returned NFTs match what we sent.
        Json::Value& nfts = aliceNFTs[jss::result][jss::account_nfts];
        if (!BEAST_EXPECT(nfts.size() == entries.size()))
            return;
 
        // Sort the returned NFTs by nft_serial so the are in the same order
        // as entries.
        std::vector<Json::Value> sortedNFTs;
        sortedNFTs.reserve(nfts.size());
        for (std::size_t i = 0; i < nfts.size(); ++i)
            sortedNFTs.push_back(nfts[i]);
        std::sort(
            sortedNFTs.begin(),
            sortedNFTs.end(),
            [](Json::Value const& lhs, Json::Value const& rhs) {
                return lhs[jss::nft_serial] < rhs[jss::nft_serial];
            });
 
        for (std::size_t i = 0; i < entries.size(); ++i)
        {
            Entry const& entry = entries[i];
            Json::Value const& ret = sortedNFTs[i];
            BEAST_EXPECT(entry.taxon == ret[sfNFTokenTaxon.jsonName]);
            if (entry.uri.empty())
            {
                BEAST_EXPECT(!ret.isMember(sfURI.jsonName));
            }
            else
            {
                BEAST_EXPECT(strHex(entry.uri) == ret[sfURI.jsonName]);
            }
        }
    }
 
    void
    testCreateOfferDestination(FeatureBitset features)
    {
        // Explore the OfferCreate Destination field.
        testcase("Create offer destination");
 
        using namespace test::jtx;
 
        Env env{*this, features};
 
        Account const issuer{"issuer"};
        Account const minter{"minter"};
        Account const buyer{"buyer"};
        Account const broker{"broker"};
 
        env.fund(XRP(1000), issuer, minter, buyer, broker);
 
        // We want to explore how issuers vs minters fits into the permission
        // scheme.  So issuer issues and minter mints.
        env(token::setMinter(issuer, minter));
        env.close();
 
        uint256 const nftokenID = token::getNextID(env, issuer, 0, tfTransferable);
        env(token::mint(minter, 0), token::issuer(issuer), txflags(tfTransferable));
        env.close();
 
        // Test how adding a Destination field to an offer affects permissions
        // for canceling offers.
        {
            uint256 const offerMinterToIssuer = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftokenID, drops(1)),
                token::destination(issuer),
                txflags(tfSellNFToken));
 
            uint256 const offerMinterToBuyer = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftokenID, drops(1)),
                token::destination(buyer),
                txflags(tfSellNFToken));
 
            uint256 const offerIssuerToMinter = keylet::nftoffer(issuer, env.seq(issuer)).key;
            env(token::createOffer(issuer, nftokenID, drops(1)),
                token::owner(minter),
                token::destination(minter));
 
            uint256 const offerIssuerToBuyer = keylet::nftoffer(issuer, env.seq(issuer)).key;
            env(token::createOffer(issuer, nftokenID, drops(1)),
                token::owner(minter),
                token::destination(buyer));
 
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 2);
            BEAST_EXPECT(ownerCount(env, minter) == 3);
            BEAST_EXPECT(ownerCount(env, buyer) == 0);
 
            // Test who gets to cancel the offers.  Anyone outside of the
            // offer-owner/destination pair should not be able to cancel the
            // offers.
            //
            // Note that issuer does not have any special permissions regarding
            // offer cancellation.  issuer cannot cancel an offer for an
            // NFToken they issued.
            env(token::cancelOffer(issuer, {offerMinterToBuyer}), ter(tecNO_PERMISSION));
            env(token::cancelOffer(buyer, {offerMinterToIssuer}), ter(tecNO_PERMISSION));
            env(token::cancelOffer(buyer, {offerIssuerToMinter}), ter(tecNO_PERMISSION));
            env(token::cancelOffer(minter, {offerIssuerToBuyer}), ter(tecNO_PERMISSION));
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 2);
            BEAST_EXPECT(ownerCount(env, minter) == 3);
            BEAST_EXPECT(ownerCount(env, buyer) == 0);
 
            // Both the offer creator and and destination should be able to
            // cancel the offers.
            env(token::cancelOffer(buyer, {offerMinterToBuyer}));
            env(token::cancelOffer(minter, {offerMinterToIssuer}));
            env(token::cancelOffer(buyer, {offerIssuerToBuyer}));
            env(token::cancelOffer(issuer, {offerIssuerToMinter}));
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 1);
            BEAST_EXPECT(ownerCount(env, buyer) == 0);
        }
 
        // Test how adding a Destination field to a sell offer affects
        // accepting that offer.
        {
            uint256 const offerMinterSellsToBuyer = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftokenID, drops(1)),
                token::destination(buyer),
                txflags(tfSellNFToken));
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 2);
            BEAST_EXPECT(ownerCount(env, buyer) == 0);
 
            // issuer cannot accept a sell offer where they are not the
            // destination.
            env(token::acceptSellOffer(issuer, offerMinterSellsToBuyer), ter(tecNO_PERMISSION));
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 2);
            BEAST_EXPECT(ownerCount(env, buyer) == 0);
 
            // However buyer can accept the sell offer.
            env(token::acceptSellOffer(buyer, offerMinterSellsToBuyer));
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 0);
            BEAST_EXPECT(ownerCount(env, buyer) == 1);
        }
 
        // Test how adding a Destination field to a buy offer affects
        // accepting that offer.
        {
            uint256 const offerMinterBuysFromBuyer = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftokenID, drops(1)),
                token::owner(buyer),
                token::destination(buyer));
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 1);
            BEAST_EXPECT(ownerCount(env, buyer) == 1);
 
            // issuer cannot accept a buy offer where they are the
            // destination.
            env(token::acceptBuyOffer(issuer, offerMinterBuysFromBuyer), ter(tecNO_PERMISSION));
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 1);
            BEAST_EXPECT(ownerCount(env, buyer) == 1);
 
            // Buyer accepts minter's offer.
            env(token::acceptBuyOffer(buyer, offerMinterBuysFromBuyer));
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 1);
            BEAST_EXPECT(ownerCount(env, buyer) == 0);
 
            // If a destination other than the NFToken owner is set, that
            // destination must act as a broker.  The NFToken owner may not
            // simply accept the offer.
            uint256 const offerBuyerBuysFromMinter = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftokenID, drops(1)),
                token::owner(minter),
                token::destination(broker));
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 1);
            BEAST_EXPECT(ownerCount(env, buyer) == 1);
 
            env(token::acceptBuyOffer(minter, offerBuyerBuysFromMinter), ter(tecNO_PERMISSION));
            env.close();
 
            // Clean up the unused offer.
            env(token::cancelOffer(buyer, {offerBuyerBuysFromMinter}));
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 1);
            BEAST_EXPECT(ownerCount(env, buyer) == 0);
        }
 
        // Show that a sell offer's Destination can broker that sell offer
        // to another account.
        {
            uint256 const offerMinterToBroker = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftokenID, drops(1)),
                token::destination(broker),
                txflags(tfSellNFToken));
 
            uint256 const offerBuyerToMinter = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftokenID, drops(1)), token::owner(minter));
 
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 2);
            BEAST_EXPECT(ownerCount(env, buyer) == 1);
 
            {
                // issuer cannot broker the offers, because they are not the
                // Destination.
                env(token::brokerOffers(issuer, offerBuyerToMinter, offerMinterToBroker),
                    ter(tecNO_PERMISSION));
                env.close();
                BEAST_EXPECT(ownerCount(env, issuer) == 0);
                BEAST_EXPECT(ownerCount(env, minter) == 2);
                BEAST_EXPECT(ownerCount(env, buyer) == 1);
            }
 
            // Since broker is the sell offer's destination, they can broker
            // the two offers.
            env(token::brokerOffers(broker, offerBuyerToMinter, offerMinterToBroker));
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 0);
            BEAST_EXPECT(ownerCount(env, buyer) == 1);
        }
 
        // Show that brokered mode cannot complete a transfer where the
        // Destination doesn't match, but can complete if the Destination
        // does match.
        {
            uint256 const offerBuyerToMinter = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftokenID, drops(1)),
                token::destination(minter),
                txflags(tfSellNFToken));
 
            uint256 const offerMinterToBuyer = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftokenID, drops(1)), token::owner(buyer));
 
            uint256 const offerIssuerToBuyer = keylet::nftoffer(issuer, env.seq(issuer)).key;
            env(token::createOffer(issuer, nftokenID, drops(1)), token::owner(buyer));
 
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 1);
            BEAST_EXPECT(ownerCount(env, minter) == 1);
            BEAST_EXPECT(ownerCount(env, buyer) == 2);
 
            {
                // Cannot broker offers when the sell destination is not the
                // buyer.
                env(token::brokerOffers(broker, offerIssuerToBuyer, offerBuyerToMinter),
                    ter(tecNO_PERMISSION));
                env.close();
 
                BEAST_EXPECT(ownerCount(env, issuer) == 1);
                BEAST_EXPECT(ownerCount(env, minter) == 1);
                BEAST_EXPECT(ownerCount(env, buyer) == 2);
 
                env(token::brokerOffers(broker, offerMinterToBuyer, offerBuyerToMinter),
                    ter(tecNO_PERMISSION));
                env.close();
 
                // Buyer is successful with acceptOffer.
                env(token::acceptBuyOffer(buyer, offerMinterToBuyer));
                env.close();
 
                // Clean out the unconsumed offer.
                env(token::cancelOffer(buyer, {offerBuyerToMinter}));
                env.close();
 
                BEAST_EXPECT(ownerCount(env, issuer) == 1);
                BEAST_EXPECT(ownerCount(env, minter) == 1);
                BEAST_EXPECT(ownerCount(env, buyer) == 0);
 
                // Clean out the unconsumed offer.
                env(token::cancelOffer(issuer, {offerIssuerToBuyer}));
                env.close();
                BEAST_EXPECT(ownerCount(env, issuer) == 0);
                BEAST_EXPECT(ownerCount(env, minter) == 1);
                BEAST_EXPECT(ownerCount(env, buyer) == 0);
                return;
            }
        }
 
        // Show that if a buy and a sell offer both have the same destination,
        // then that destination can broker the offers.
        {
            uint256 const offerMinterToBroker = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftokenID, drops(1)),
                token::destination(broker),
                txflags(tfSellNFToken));
 
            uint256 const offerBuyerToBroker = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftokenID, drops(1)),
                token::owner(minter),
                token::destination(broker));
 
            {
                // Cannot broker offers when the sell destination is not the
                // buyer or the broker.
                env(token::brokerOffers(issuer, offerBuyerToBroker, offerMinterToBroker),
                    ter(tecNO_PERMISSION));
                env.close();
                BEAST_EXPECT(ownerCount(env, issuer) == 0);
                BEAST_EXPECT(ownerCount(env, minter) == 2);
                BEAST_EXPECT(ownerCount(env, buyer) == 1);
            }
 
            // Broker is successful if they are the destination of both offers.
            env(token::brokerOffers(broker, offerBuyerToBroker, offerMinterToBroker));
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 0);
            BEAST_EXPECT(ownerCount(env, buyer) == 1);
        }
    }
 
    void
    testCreateOfferDestinationDisallowIncoming(FeatureBitset features)
    {
        testcase("Create offer destination disallow incoming");
 
        using namespace test::jtx;
 
        Env env{*this, features};
 
        Account const issuer{"issuer"};
        Account const minter{"minter"};
        Account const buyer{"buyer"};
        Account const alice{"alice"};
 
        env.fund(XRP(1000), issuer, minter, buyer, alice);
 
        env(token::setMinter(issuer, minter));
        env.close();
 
        uint256 const nftokenID = token::getNextID(env, issuer, 0, tfTransferable);
        env(token::mint(minter, 0), token::issuer(issuer), txflags(tfTransferable));
        env.close();
 
        // enable flag
        env(fset(buyer, asfDisallowIncomingNFTokenOffer));
        env.close();
 
        // a sell offer from the minter to the buyer should be rejected
        {
            env(token::createOffer(minter, nftokenID, drops(1)),
                token::destination(buyer),
                txflags(tfSellNFToken),
                ter(tecNO_PERMISSION));
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 1);
            BEAST_EXPECT(ownerCount(env, buyer) == 0);
        }
 
        // disable the flag
        env(fclear(buyer, asfDisallowIncomingNFTokenOffer));
        env.close();
 
        // create offer (allowed now) then cancel
        {
            uint256 const offerIndex = keylet::nftoffer(minter, env.seq(minter)).key;
 
            env(token::createOffer(minter, nftokenID, drops(1)),
                token::destination(buyer),
                txflags(tfSellNFToken));
            env.close();
 
            env(token::cancelOffer(minter, {offerIndex}));
            env.close();
        }
 
        // create offer, enable flag, then cancel
        {
            uint256 const offerIndex = keylet::nftoffer(minter, env.seq(minter)).key;
 
            env(token::createOffer(minter, nftokenID, drops(1)),
                token::destination(buyer),
                txflags(tfSellNFToken));
            env.close();
 
            env(fset(buyer, asfDisallowIncomingNFTokenOffer));
            env.close();
 
            env(token::cancelOffer(minter, {offerIndex}));
            env.close();
 
            env(fclear(buyer, asfDisallowIncomingNFTokenOffer));
            env.close();
        }
 
        // create offer then transfer
        {
            uint256 const offerIndex = keylet::nftoffer(minter, env.seq(minter)).key;
 
            env(token::createOffer(minter, nftokenID, drops(1)),
                token::destination(buyer),
                txflags(tfSellNFToken));
            env.close();
 
            env(token::acceptSellOffer(buyer, offerIndex));
            env.close();
        }
 
        // buyer now owns the token
 
        // enable flag again
        env(fset(buyer, asfDisallowIncomingNFTokenOffer));
        env.close();
 
        // a random offer to buy the token
        {
            env(token::createOffer(alice, nftokenID, drops(1)),
                token::owner(buyer),
                ter(tecNO_PERMISSION));
            env.close();
        }
 
        // minter offer to buy the token
        {
            env(token::createOffer(minter, nftokenID, drops(1)),
                token::owner(buyer),
                ter(tecNO_PERMISSION));
            env.close();
        }
 
        // minter mint and offer to buyer
        if (features[featureNFTokenMintOffer])
        {
            // enable flag
            env(fset(buyer, asfDisallowIncomingNFTokenOffer));
            // a sell offer from the minter to the buyer should be rejected
            env(token::mint(minter),
                token::amount(drops(1)),
                token::destination(buyer),
                ter(tecNO_PERMISSION));
            env.close();
 
            // disable flag
            env(fclear(buyer, asfDisallowIncomingNFTokenOffer));
            env(token::mint(minter), token::amount(drops(1)), token::destination(buyer));
            env.close();
        }
    }
 
    void
    testCreateOfferExpiration(FeatureBitset features)
    {
        // Explore the OfferCreate Expiration field.
        testcase("Create offer expiration");
 
        using namespace test::jtx;
 
        Env env{*this, features};
 
        Account const issuer{"issuer"};
        Account const minter{"minter"};
        Account const buyer{"buyer"};
 
        env.fund(XRP(1000), issuer, minter, buyer);
 
        // We want to explore how issuers vs minters fits into the permission
        // scheme.  So issuer issues and minter mints.
        env(token::setMinter(issuer, minter));
        env.close();
 
        uint256 const nftokenID0 = token::getNextID(env, issuer, 0, tfTransferable);
        env(token::mint(minter, 0), token::issuer(issuer), txflags(tfTransferable));
        env.close();
 
        uint256 const nftokenID1 = token::getNextID(env, issuer, 0, tfTransferable);
        env(token::mint(minter, 0), token::issuer(issuer), txflags(tfTransferable));
        env.close();
        uint8_t issuerCount = 0, minterCount = 0, buyerCount = 0;
 
        // Test how adding an Expiration field to an offer affects permissions
        // for cancelling offers.
        {
            std::uint32_t const expiration = lastClose(env) + 25;
 
            uint256 const offerMinterToIssuer = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftokenID0, drops(1)),
                token::destination(issuer),
                token::expiration(expiration),
                txflags(tfSellNFToken));
 
            uint256 const offerMinterToAnyone = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftokenID0, drops(1)),
                token::expiration(expiration),
                txflags(tfSellNFToken));
 
            uint256 const offerIssuerToMinter = keylet::nftoffer(issuer, env.seq(issuer)).key;
            env(token::createOffer(issuer, nftokenID0, drops(1)),
                token::owner(minter),
                token::expiration(expiration));
 
            uint256 const offerBuyerToMinter = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftokenID0, drops(1)),
                token::owner(minter),
                token::expiration(expiration));
            env.close();
            issuerCount = 1;
            minterCount = 3;
            buyerCount = 1;
            BEAST_EXPECT(ownerCount(env, issuer) == issuerCount);
            BEAST_EXPECT(ownerCount(env, minter) == minterCount);
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            // Test who gets to cancel the offers.  Anyone outside of the
            // offer-owner/destination pair should not be able to cancel
            // unexpired offers.
            //
            // Note that these are tec responses, so these transactions will
            // not be retried by the ledger.
            env(token::cancelOffer(issuer, {offerMinterToAnyone}), ter(tecNO_PERMISSION));
            env(token::cancelOffer(buyer, {offerIssuerToMinter}), ter(tecNO_PERMISSION));
            env.close();
            BEAST_EXPECT(lastClose(env) < expiration);
            BEAST_EXPECT(ownerCount(env, issuer) == issuerCount);
            BEAST_EXPECT(ownerCount(env, minter) == minterCount);
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            // The offer creator can cancel their own unexpired offer.
            env(token::cancelOffer(minter, {offerMinterToAnyone}));
            minterCount--;
 
            // The destination of a sell offer can cancel the NFT owner's
            // unexpired offer.
            env(token::cancelOffer(issuer, {offerMinterToIssuer}));
            minterCount--;
 
            // Close enough ledgers to get past the expiration.
            while (lastClose(env) < expiration)
                env.close();
 
            BEAST_EXPECT(ownerCount(env, issuer) == issuerCount);
            BEAST_EXPECT(ownerCount(env, minter) == minterCount);
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            // Anyone can cancel expired offers.
            env(token::cancelOffer(issuer, {offerBuyerToMinter}));
            buyerCount--;
            env(token::cancelOffer(buyer, {offerIssuerToMinter}));
            issuerCount--;
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == issuerCount);
            BEAST_EXPECT(ownerCount(env, minter) == minterCount);
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
        }
        // Show that:
        //  1. An unexpired sell offer with an expiration can be accepted.
        //  2. An expired sell offer cannot be accepted and remains
        //     in ledger after the accept fails.
        {
            std::uint32_t const expiration = lastClose(env) + 25;
 
            uint256 const offer0 = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftokenID0, drops(1)),
                token::expiration(expiration),
                txflags(tfSellNFToken));
            minterCount++;
 
            uint256 const offer1 = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftokenID1, drops(1)),
                token::expiration(expiration),
                txflags(tfSellNFToken));
            minterCount++;
            env.close();
            BEAST_EXPECT(lastClose(env) < expiration);
            BEAST_EXPECT(ownerCount(env, issuer) == issuerCount);
            BEAST_EXPECT(ownerCount(env, minter) == minterCount);
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            // Anyone can accept an unexpired sell offer.
            env(token::acceptSellOffer(buyer, offer0));
            minterCount--;
            buyerCount++;
 
            // Close enough ledgers to get past the expiration.
            while (lastClose(env) < expiration)
                env.close();
 
            BEAST_EXPECT(ownerCount(env, issuer) == issuerCount);
            BEAST_EXPECT(ownerCount(env, minter) == minterCount);
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            // No one can accept an expired sell offer.
            env(token::acceptSellOffer(buyer, offer1), ter(tecEXPIRED));
 
            // With fixExpiredNFTokenOfferRemoval amendment, the first accept
            // attempt deletes the expired offer. Without the amendment,
            // the offer remains and we can try to accept it again.
            if (features[fixExpiredNFTokenOfferRemoval])
            {
                // After amendment: offer was deleted by first accept attempt
                minterCount--;
                env(token::acceptSellOffer(issuer, offer1), ter(tecOBJECT_NOT_FOUND));
            }
            else
            {
                // Before amendment: offer still exists, second accept also
                // fails
                env(token::acceptSellOffer(issuer, offer1), ter(tecEXPIRED));
            }
            env.close();
 
            // Check if the expired sell offer behavior matches amendment status
            BEAST_EXPECT(ownerCount(env, issuer) == issuerCount);
            BEAST_EXPECT(ownerCount(env, minter) == minterCount);
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            if (!features[fixExpiredNFTokenOfferRemoval])
            {
                // Before amendment: expired offer still exists and needs to be
                // cancelled
                env(token::cancelOffer(issuer, {offer1}));
                env.close();
                minterCount--;
            }
            // Ensure that owner counts are correct with and without the
            // amendment
            BEAST_EXPECT(ownerCount(env, issuer) == 0 && issuerCount == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 1 && minterCount == 1);
            BEAST_EXPECT(ownerCount(env, buyer) == 1 && buyerCount == 1);
 
            // Transfer nftokenID0 back to minter so we start the next test in
            // a simple place.
            uint256 const offerSellBack = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftokenID0, XRP(0)),
                txflags(tfSellNFToken),
                token::destination(minter));
            env.close();
            env(token::acceptSellOffer(minter, offerSellBack));
            buyerCount--;
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == issuerCount);
            BEAST_EXPECT(ownerCount(env, minter) == minterCount);
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
        }
        // Show that:
        //  1. An unexpired buy offer with an expiration can be accepted.
        //  2. An expired buy offer cannot be accepted and remains
        //     in ledger after the accept fails.
        {
            std::uint32_t const expiration = lastClose(env) + 25;
 
            uint256 const offer0 = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftokenID0, drops(1)),
                token::owner(minter),
                token::expiration(expiration));
            buyerCount++;
 
            uint256 const offer1 = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftokenID1, drops(1)),
                token::owner(minter),
                token::expiration(expiration));
            buyerCount++;
            env.close();
            BEAST_EXPECT(lastClose(env) < expiration);
            BEAST_EXPECT(ownerCount(env, issuer) == issuerCount);
            BEAST_EXPECT(ownerCount(env, minter) == minterCount);
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            // An unexpired buy offer can be accepted.
            env(token::acceptBuyOffer(minter, offer0));
 
            // Close enough ledgers to get past the expiration.
            while (lastClose(env) < expiration)
                env.close();
 
            BEAST_EXPECT(ownerCount(env, issuer) == issuerCount);
            BEAST_EXPECT(ownerCount(env, minter) == minterCount);
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            // An expired buy offer cannot be accepted.
            env(token::acceptBuyOffer(minter, offer1), ter(tecEXPIRED));
 
            // With fixExpiredNFTokenOfferRemoval amendment, the first accept
            // attempt deletes the expired offer. Without the amendment,
            // the offer remains and we can try to accept it again.
            if (features[fixExpiredNFTokenOfferRemoval])
            {
                // After amendment: offer was deleted by first accept attempt
                buyerCount--;
                env(token::acceptBuyOffer(issuer, offer1), ter(tecOBJECT_NOT_FOUND));
            }
            else
            {
                // Before amendment: offer still exists, second accept also
                // fails
                env(token::acceptBuyOffer(issuer, offer1), ter(tecEXPIRED));
            }
            env.close();
 
            // Check if the expired buy offer behavior matches amendment status
            BEAST_EXPECT(ownerCount(env, issuer) == issuerCount);
            BEAST_EXPECT(ownerCount(env, minter) == minterCount);
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            if (!features[fixExpiredNFTokenOfferRemoval])
            {
                // Before amendment: expired offer still exists and can be
                // cancelled
                env(token::cancelOffer(issuer, {offer1}));
                env.close();
                buyerCount--;
            }
            // Ensure that owner counts are the same with and without the
            // amendment
            BEAST_EXPECT(ownerCount(env, issuer) == 0 && issuerCount == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 1 && minterCount == 1);
            BEAST_EXPECT(ownerCount(env, buyer) == 1 && buyerCount == 1);
 
            // Transfer nftokenID0 back to minter so we start the next test in
            // a simple place.
            uint256 const offerSellBack = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftokenID0, XRP(0)),
                txflags(tfSellNFToken),
                token::destination(minter));
            env.close();
            env(token::acceptSellOffer(minter, offerSellBack));
            env.close();
            buyerCount--;
            BEAST_EXPECT(ownerCount(env, issuer) == issuerCount);
            BEAST_EXPECT(ownerCount(env, minter) == minterCount);
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
        }
        // Show that in brokered mode:
        //  1. An unexpired sell offer with an expiration can be accepted.
        //  2. An expired sell offer cannot be accepted and remains
        //     in ledger after the accept fails.
        {
            std::uint32_t const expiration = lastClose(env) + 25;
 
            uint256 const sellOffer0 = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftokenID0, drops(1)),
                token::expiration(expiration),
                txflags(tfSellNFToken));
            minterCount++;
 
            uint256 const sellOffer1 = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftokenID1, drops(1)),
                token::expiration(expiration),
                txflags(tfSellNFToken));
            minterCount++;
 
            uint256 const buyOffer0 = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftokenID0, drops(1)), token::owner(minter));
            buyerCount++;
 
            uint256 const buyOffer1 = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftokenID1, drops(1)), token::owner(minter));
            buyerCount++;
 
            env.close();
            BEAST_EXPECT(lastClose(env) < expiration);
            BEAST_EXPECT(ownerCount(env, issuer) == issuerCount);
            BEAST_EXPECT(ownerCount(env, minter) == minterCount);
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            // An unexpired offer can be brokered.
            env(token::brokerOffers(issuer, buyOffer0, sellOffer0));
            minterCount--;
 
            // Close enough ledgers to get past the expiration.
            while (lastClose(env) < expiration)
                env.close();
 
            BEAST_EXPECT(ownerCount(env, issuer) == issuerCount);
            BEAST_EXPECT(ownerCount(env, minter) == minterCount);
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            // If the sell offer is expired it cannot be brokered.
            env(token::brokerOffers(issuer, buyOffer1, sellOffer1), ter(tecEXPIRED));
            env.close();
 
            if (features[fixExpiredNFTokenOfferRemoval])
            {
                // With amendment: expired offers are deleted
                minterCount--;
            }
 
            BEAST_EXPECT(ownerCount(env, issuer) == issuerCount);
            BEAST_EXPECT(ownerCount(env, minter) == minterCount);
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
 
            if (features[fixExpiredNFTokenOfferRemoval])
            {
                // The buy offer was deleted, so no need to cancel it
                // The sell offer still exists, so we can cancel it
                env(token::cancelOffer(buyer, {buyOffer1}));
                buyerCount--;
            }
            else
            {
                // Anyone can cancel the expired offers
                env(token::cancelOffer(buyer, {buyOffer1, sellOffer1}));
                minterCount--;
                buyerCount--;
            }
            env.close();
            // Ensure that owner counts are the same with and without the
            // amendment
            BEAST_EXPECT(ownerCount(env, issuer) == 0 && issuerCount == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 1 && minterCount == 1);
            BEAST_EXPECT(ownerCount(env, buyer) == 1 && buyerCount == 1);
 
            // Transfer nftokenID0 back to minter so we start the next test in
            // a simple place.
            uint256 const offerSellBack = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftokenID0, XRP(0)),
                txflags(tfSellNFToken),
                token::destination(minter));
            env.close();
            env(token::acceptSellOffer(minter, offerSellBack));
            env.close();
            buyerCount--;
            BEAST_EXPECT(ownerCount(env, issuer) == issuerCount);
            BEAST_EXPECT(ownerCount(env, minter) == minterCount);
            BEAST_EXPECT(ownerCount(env, buyer) == buyerCount);
        }
        // Show that in brokered mode:
        //  1. An unexpired buy offer with an expiration can be accepted.
        //  2. An expired buy offer cannot be accepted and remains
        //     in ledger after the accept fails.
        {
            std::uint32_t const expiration = lastClose(env) + 25;
 
            uint256 const sellOffer0 = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftokenID0, drops(1)), txflags(tfSellNFToken));
 
            uint256 const sellOffer1 = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftokenID1, drops(1)), txflags(tfSellNFToken));
 
            uint256 const buyOffer0 = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftokenID0, drops(1)),
                token::expiration(expiration),
                token::owner(minter));
 
            uint256 const buyOffer1 = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftokenID1, drops(1)),
                token::expiration(expiration),
                token::owner(minter));
 
            env.close();
            BEAST_EXPECT(lastClose(env) < expiration);
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 3);
            BEAST_EXPECT(ownerCount(env, buyer) == 2);
 
            // An unexpired offer can be brokered.
            env(token::brokerOffers(issuer, buyOffer0, sellOffer0));
 
            // Close enough ledgers to get past the expiration.
            while (lastClose(env) < expiration)
                env.close();
 
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 2);
            BEAST_EXPECT(ownerCount(env, buyer) == 2);
 
            env(token::brokerOffers(issuer, buyOffer1, sellOffer1), ter(tecEXPIRED));
            env.close();
 
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            if (features[fixExpiredNFTokenOfferRemoval])
            {
                // After amendment: expired offers were deleted during broker
                // attempt
                BEAST_EXPECT(ownerCount(env, minter) == 2);
                BEAST_EXPECT(ownerCount(env, buyer) == 1);
                // The buy offer was deleted, so no need to cancel it
                // The sell offer still exists, so we can cancel it
                env(token::cancelOffer(minter, {sellOffer1}));
            }
            else
            {
                // Before amendment: expired offers still exist in ledger
                BEAST_EXPECT(ownerCount(env, minter) == 2);
                BEAST_EXPECT(ownerCount(env, buyer) == 2);
                // Anyone can cancel the expired offers
                env(token::cancelOffer(minter, {buyOffer1, sellOffer1}));
            }
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 1);
            BEAST_EXPECT(ownerCount(env, buyer) == 1);
 
            // Transfer nftokenID0 back to minter so we start the next test in
            // a simple place.
            uint256 const offerSellBack = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftokenID0, XRP(0)),
                txflags(tfSellNFToken),
                token::destination(minter));
            env.close();
            env(token::acceptSellOffer(minter, offerSellBack));
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 1);
            BEAST_EXPECT(ownerCount(env, buyer) == 0);
        }
        // Show that in brokered mode:
        //  1. An unexpired buy/sell offer pair with an expiration can be
        //     accepted.
        //  2. An expired buy/sell offer pair cannot be accepted and they
        //     remain in ledger after the accept fails.
        {
            std::uint32_t const expiration = lastClose(env) + 25;
 
            uint256 const sellOffer0 = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftokenID0, drops(1)),
                token::expiration(expiration),
                txflags(tfSellNFToken));
 
            uint256 const sellOffer1 = keylet::nftoffer(minter, env.seq(minter)).key;
            env(token::createOffer(minter, nftokenID1, drops(1)),
                token::expiration(expiration),
                txflags(tfSellNFToken));
 
            uint256 const buyOffer0 = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftokenID0, drops(1)),
                token::expiration(expiration),
                token::owner(minter));
 
            uint256 const buyOffer1 = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftokenID1, drops(1)),
                token::expiration(expiration),
                token::owner(minter));
 
            env.close();
            BEAST_EXPECT(lastClose(env) < expiration);
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 3);
            BEAST_EXPECT(ownerCount(env, buyer) == 2);
 
            // Unexpired offers can be brokered.
            env(token::brokerOffers(issuer, buyOffer0, sellOffer0));
 
            // Close enough ledgers to get past the expiration.
            while (lastClose(env) < expiration)
                env.close();
 
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 2);
            BEAST_EXPECT(ownerCount(env, buyer) == 2);
 
            env(token::brokerOffers(issuer, buyOffer1, sellOffer1), ter(tecEXPIRED));
            env.close();
 
            // The expired offers are still in the ledger.
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            if (!features[fixExpiredNFTokenOfferRemoval])
            {
                // Before amendment: expired offers still exist in ledger
                BEAST_EXPECT(ownerCount(env, minter) == 2);
                BEAST_EXPECT(ownerCount(env, buyer) == 2);
                // Anyone can cancel the expired offers
                env(token::cancelOffer(issuer, {buyOffer1, sellOffer1}));
            }
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 1);
            BEAST_EXPECT(ownerCount(env, buyer) == 1);
 
            // Transfer nftokenID0 back to minter so we start the next test in
            // a simple place.
            uint256 const offerSellBack = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftokenID0, XRP(0)),
                txflags(tfSellNFToken),
                token::destination(minter));
            env.close();
            env(token::acceptSellOffer(minter, offerSellBack));
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            BEAST_EXPECT(ownerCount(env, minter) == 1);
            BEAST_EXPECT(ownerCount(env, buyer) == 0);
        }
    }
 
    void
    testCancelOffers(FeatureBitset features)
    {
        // Look at offer canceling.
        testcase("Cancel offers");
 
        using namespace test::jtx;
 
        Env env{*this, features};
 
        Account const alice("alice");
        Account const becky("becky");
        Account const minter("minter");
        env.fund(XRP(50000), alice, becky, minter);
        env.close();
 
        // alice has a minter to see if minters have offer canceling permission.
        env(token::setMinter(alice, minter));
        env.close();
 
        uint256 const nftokenID = token::getNextID(env, alice, 0, tfTransferable);
        env(token::mint(alice, 0), txflags(tfTransferable));
        env.close();
 
        // Anyone can cancel an expired offer.
        uint256 const expiredOfferIndex = keylet::nftoffer(alice, env.seq(alice)).key;
 
        env(token::createOffer(alice, nftokenID, XRP(1000)),
            txflags(tfSellNFToken),
            token::expiration(lastClose(env) + 13));
        env.close();
 
        // The offer has not expired yet, so becky can't cancel it now.
        BEAST_EXPECT(ownerCount(env, alice) == 2);
        env(token::cancelOffer(becky, {expiredOfferIndex}), ter(tecNO_PERMISSION));
        env.close();
 
        // Close a couple of ledgers and advance the time.  Then becky
        // should be able to cancel the (now) expired offer.
        env.close();
        env.close();
        env(token::cancelOffer(becky, {expiredOfferIndex}));
        env.close();
        BEAST_EXPECT(ownerCount(env, alice) == 1);
 
        // Create a couple of offers with a destination.  Those offers
        // should be cancellable by the creator and the destination.
        uint256 const dest1OfferIndex = keylet::nftoffer(alice, env.seq(alice)).key;
 
        env(token::createOffer(alice, nftokenID, XRP(1000)),
            token::destination(becky),
            txflags(tfSellNFToken));
        env.close();
        BEAST_EXPECT(ownerCount(env, alice) == 2);
 
        // Minter can't cancel that offer, but becky (the destination) can.
        env(token::cancelOffer(minter, {dest1OfferIndex}), ter(tecNO_PERMISSION));
        env.close();
        BEAST_EXPECT(ownerCount(env, alice) == 2);
 
        env(token::cancelOffer(becky, {dest1OfferIndex}));
        env.close();
        BEAST_EXPECT(ownerCount(env, alice) == 1);
 
        // alice can cancel her own offer, even if becky is the destination.
        uint256 const dest2OfferIndex = keylet::nftoffer(alice, env.seq(alice)).key;
 
        env(token::createOffer(alice, nftokenID, XRP(1000)),
            token::destination(becky),
            txflags(tfSellNFToken));
        env.close();
        BEAST_EXPECT(ownerCount(env, alice) == 2);
 
        env(token::cancelOffer(alice, {dest2OfferIndex}));
        env.close();
        BEAST_EXPECT(ownerCount(env, alice) == 1);
 
        // The issuer has no special permissions regarding offer cancellation.
        // Minter creates a token with alice as issuer.  alice cannot cancel
        // minter's offer.
        uint256 const mintersNFTokenID = token::getNextID(env, alice, 0, tfTransferable);
        env(token::mint(minter, 0), token::issuer(alice), txflags(tfTransferable));
        env.close();
 
        uint256 const minterOfferIndex = keylet::nftoffer(minter, env.seq(minter)).key;
 
        env(token::createOffer(minter, mintersNFTokenID, XRP(1000)), txflags(tfSellNFToken));
        env.close();
        BEAST_EXPECT(ownerCount(env, minter) == 2);
 
        // Nobody other than minter should be able to cancel minter's offer.
        env(token::cancelOffer(alice, {minterOfferIndex}), ter(tecNO_PERMISSION));
        env(token::cancelOffer(becky, {minterOfferIndex}), ter(tecNO_PERMISSION));
        env.close();
        BEAST_EXPECT(ownerCount(env, minter) == 2);
 
        env(token::cancelOffer(minter, {minterOfferIndex}));
        env.close();
        BEAST_EXPECT(ownerCount(env, minter) == 1);
    }
 
    void
    testCancelTooManyOffers(FeatureBitset features)
    {
        // Look at the case where too many offers are passed in a cancel.
        testcase("Cancel too many offers");
 
        using namespace test::jtx;
 
        Env env{*this, features};
 
        // We want to maximize the metadata from a cancel offer transaction to
        // make sure we don't hit metadata limits.  The way we'll do that is:
        //
        //  1. Generate twice as many separate funded accounts as we have
        //     offers.
        //  2.
        //     a. One of these accounts mints an NFT with a full URL.
        //     b. The other account makes an offer that will expire soon.
        //  3. After all of these offers have expired, cancel all of the
        //     expired offers in a single transaction.
        //
        // I can't think of any way to increase the metadata beyond this,
        // but I'm open to ideas.
        Account const alice("alice");
        env.fund(XRP(1000), alice);
        env.close();
 
        std::string const uri(maxTokenURILength, '?');
        std::vector<uint256> offerIndexes;
        offerIndexes.reserve(maxTokenOfferCancelCount + 1);
        for (uint32_t i = 0; i < maxTokenOfferCancelCount + 1; ++i)
        {
            Account const nftAcct(std::string("nftAcct") + std::to_string(i));
            Account const offerAcct(std::string("offerAcct") + std::to_string(i));
            env.fund(XRP(1000), nftAcct, offerAcct);
            env.close();
 
            uint256 const nftokenID = token::getNextID(env, nftAcct, 0, tfTransferable);
            env(token::mint(nftAcct, 0), token::uri(uri), txflags(tfTransferable));
            env.close();
 
            offerIndexes.push_back(keylet::nftoffer(offerAcct, env.seq(offerAcct)).key);
            env(token::createOffer(offerAcct, nftokenID, drops(1)),
                token::owner(nftAcct),
                token::expiration(lastClose(env) + 5));
            env.close();
        }
 
        // Close the ledger so the last of the offers expire.
        env.close();
 
        // All offers should be in the ledger.
        for (uint256 const& offerIndex : offerIndexes)
        {
            BEAST_EXPECT(env.le(keylet::nftoffer(offerIndex)));
        }
 
        // alice attempts to cancel all of the expired offers.  There is one
        // too many so the request fails.
        env(token::cancelOffer(alice, offerIndexes), ter(temMALFORMED));
        env.close();
 
        // However alice can cancel just one of the offers.
        env(token::cancelOffer(alice, {offerIndexes.back()}));
        env.close();
 
        // Verify that offer is gone from the ledger.
        BEAST_EXPECT(!env.le(keylet::nftoffer(offerIndexes.back())));
        offerIndexes.pop_back();
 
        // But alice adds a sell offer to the list...
        {
            uint256 const nftokenID = token::getNextID(env, alice, 0, tfTransferable);
            env(token::mint(alice, 0), token::uri(uri), txflags(tfTransferable));
            env.close();
 
            offerIndexes.push_back(keylet::nftoffer(alice, env.seq(alice)).key);
            env(token::createOffer(alice, nftokenID, drops(1)), txflags(tfSellNFToken));
            env.close();
 
            // alice's owner count should now to 2 for the nft and the offer.
            BEAST_EXPECT(ownerCount(env, alice) == 2);
 
            // Because alice added the sell offer there are still too many
            // offers in the list to cancel.
            env(token::cancelOffer(alice, offerIndexes), ter(temMALFORMED));
            env.close();
 
            // alice burns her nft which removes the nft and the offer.
            env(token::burn(alice, nftokenID));
            env.close();
 
            // If alice's owner count is zero we can see that the offer
            // and nft are both gone.
            BEAST_EXPECT(ownerCount(env, alice) == 0);
            offerIndexes.pop_back();
        }
 
        // Now there are few enough offers in the list that they can all
        // be cancelled in a single transaction.
        env(token::cancelOffer(alice, offerIndexes));
        env.close();
 
        // Verify that remaining offers are gone from the ledger.
        for (uint256 const& offerIndex : offerIndexes)
        {
            BEAST_EXPECT(!env.le(keylet::nftoffer(offerIndex)));
        }
    }
 
    void
    testBrokeredAccept(FeatureBitset features)
    {
        // Look at the case where too many offers are passed in a cancel.
        testcase("Brokered NFT offer accept");
 
        using namespace test::jtx;
 
        {
            Env env{*this, features};
            auto const baseFee = env.current()->fees().base;
 
            // The most important thing to explore here is the way funds are
            // assigned from the buyer to...
            //  o the Seller,
            //  o the Broker, and
            //  o the Issuer (in the case of a transfer fee).
 
            Account const issuer{"issuer"};
            Account const minter{"minter"};
            Account const buyer{"buyer"};
            Account const broker{"broker"};
            Account const gw{"gw"};
            IOU const gwXAU(gw["XAU"]);
 
            env.fund(XRP(1000), issuer, minter, buyer, broker, gw);
            env.close();
 
            env(trust(issuer, gwXAU(2000)));
            env(trust(minter, gwXAU(2000)));
            env(trust(buyer, gwXAU(2000)));
            env(trust(broker, gwXAU(2000)));
            env.close();
 
            env(token::setMinter(issuer, minter));
            env.close();
 
            // Lambda to check owner count of all accounts is one.
            auto checkOwnerCountIsOne =
                [this, &env](
                    std::initializer_list<std::reference_wrapper<Account const>> accounts,
                    int line) {
                    for (Account const& acct : accounts)
                    {
                        if (std::uint32_t const ownerCount = test::jtx::ownerCount(env, acct);
                            ownerCount != 1)
                        {
                            std::stringstream ss;
                            ss << "Account " << acct.human() << " expected ownerCount == 1.  Got "
                               << ownerCount;
                            fail(ss.str(), __FILE__, line);
                        }
                    }
                };
 
            // Lambda that mints an NFT and returns the nftID.
            auto mintNFT = [&env, &issuer, &minter](std::uint16_t xferFee = 0) {
                uint256 const nftID = token::getNextID(env, issuer, 0, tfTransferable, xferFee);
                env(token::mint(minter, 0),
                    token::issuer(issuer),
                    token::xferFee(xferFee),
                    txflags(tfTransferable));
                env.close();
                return nftID;
            };
 
            // o Seller is selling for zero XRP.
            // o Broker charges no fee.
            // o No transfer fee.
            //
            // Since minter is selling for zero the currency must be XRP.
            {
                checkOwnerCountIsOne({issuer, minter, buyer, broker}, __LINE__);
 
                uint256 const nftID = mintNFT();
 
                // minter creates their offer.
                uint256 const minterOfferIndex = keylet::nftoffer(minter, env.seq(minter)).key;
                env(token::createOffer(minter, nftID, XRP(0)), txflags(tfSellNFToken));
                env.close();
 
                // buyer creates their offer.  Note: a buy offer can never
                // offer zero.
                uint256 const buyOfferIndex = keylet::nftoffer(buyer, env.seq(buyer)).key;
                env(token::createOffer(buyer, nftID, XRP(1)), token::owner(minter));
                env.close();
 
                auto const minterBalance = env.balance(minter);
                auto const buyerBalance = env.balance(buyer);
                auto const brokerBalance = env.balance(broker);
                auto const issuerBalance = env.balance(issuer);
 
                // Broker charges no brokerFee.
                env(token::brokerOffers(broker, buyOfferIndex, minterOfferIndex));
                env.close();
 
                // Note that minter's XRP balance goes up even though they
                // requested XRP(0).
                BEAST_EXPECT(env.balance(minter) == minterBalance + XRP(1));
                BEAST_EXPECT(env.balance(buyer) == buyerBalance - XRP(1));
                BEAST_EXPECT(env.balance(broker) == brokerBalance - baseFee);
                BEAST_EXPECT(env.balance(issuer) == issuerBalance);
 
                // Burn the NFT so the next test starts with a clean state.
                env(token::burn(buyer, nftID));
                env.close();
            }
 
            // o Seller is selling for zero XRP.
            // o Broker charges a fee.
            // o No transfer fee.
            //
            // Since minter is selling for zero the currency must be XRP.
            {
                checkOwnerCountIsOne({issuer, minter, buyer, broker}, __LINE__);
 
                uint256 const nftID = mintNFT();
 
                // minter creates their offer.
                uint256 const minterOfferIndex = keylet::nftoffer(minter, env.seq(minter)).key;
                env(token::createOffer(minter, nftID, XRP(0)), txflags(tfSellNFToken));
                env.close();
 
                // buyer creates their offer.  Note: a buy offer can never
                // offer zero.
                uint256 const buyOfferIndex = keylet::nftoffer(buyer, env.seq(buyer)).key;
                env(token::createOffer(buyer, nftID, XRP(1)), token::owner(minter));
                env.close();
 
                // Broker attempts to charge a 1.1 XRP brokerFee and fails.
                env(token::brokerOffers(broker, buyOfferIndex, minterOfferIndex),
                    token::brokerFee(XRP(1.1)),
                    ter(tecINSUFFICIENT_PAYMENT));
                env.close();
 
                auto const minterBalance = env.balance(minter);
                auto const buyerBalance = env.balance(buyer);
                auto const brokerBalance = env.balance(broker);
                auto const issuerBalance = env.balance(issuer);
 
                // Broker charges a 0.5 XRP brokerFee.
                env(token::brokerOffers(broker, buyOfferIndex, minterOfferIndex),
                    token::brokerFee(XRP(0.5)));
                env.close();
 
                // Note that minter's XRP balance goes up even though they
                // requested XRP(0).
                BEAST_EXPECT(env.balance(minter) == minterBalance + XRP(0.5));
                BEAST_EXPECT(env.balance(buyer) == buyerBalance - XRP(1));
                BEAST_EXPECT(env.balance(broker) == brokerBalance + XRP(0.5) - baseFee);
                BEAST_EXPECT(env.balance(issuer) == issuerBalance);
 
                // Burn the NFT so the next test starts with a clean state.
                env(token::burn(buyer, nftID));
                env.close();
            }
 
            // o Seller is selling for zero XRP.
            // o Broker charges no fee.
            // o 50% transfer fee.
            //
            // Since minter is selling for zero the currency must be XRP.
            {
                checkOwnerCountIsOne({issuer, minter, buyer, broker}, __LINE__);
 
                uint256 const nftID = mintNFT(maxTransferFee);
 
                // minter creates their offer.
                uint256 const minterOfferIndex = keylet::nftoffer(minter, env.seq(minter)).key;
                env(token::createOffer(minter, nftID, XRP(0)), txflags(tfSellNFToken));
                env.close();
 
                // buyer creates their offer.  Note: a buy offer can never
                // offer zero.
                uint256 const buyOfferIndex = keylet::nftoffer(buyer, env.seq(buyer)).key;
                env(token::createOffer(buyer, nftID, XRP(1)), token::owner(minter));
                env.close();
 
                auto const minterBalance = env.balance(minter);
                auto const buyerBalance = env.balance(buyer);
                auto const brokerBalance = env.balance(broker);
                auto const issuerBalance = env.balance(issuer);
 
                // Broker charges no brokerFee.
                env(token::brokerOffers(broker, buyOfferIndex, minterOfferIndex));
                env.close();
 
                // Note that minter's XRP balance goes up even though they
                // requested XRP(0).
                BEAST_EXPECT(env.balance(minter) == minterBalance + XRP(0.5));
                BEAST_EXPECT(env.balance(buyer) == buyerBalance - XRP(1));
                BEAST_EXPECT(env.balance(broker) == brokerBalance - baseFee);
                BEAST_EXPECT(env.balance(issuer) == issuerBalance + XRP(0.5));
 
                // Burn the NFT so the next test starts with a clean state.
                env(token::burn(buyer, nftID));
                env.close();
            }
 
            // o Seller is selling for zero XRP.
            // o Broker charges 0.5 XRP.
            // o 50% transfer fee.
            //
            // Since minter is selling for zero the currency must be XRP.
            {
                checkOwnerCountIsOne({issuer, minter, buyer, broker}, __LINE__);
 
                uint256 const nftID = mintNFT(maxTransferFee);
 
                // minter creates their offer.
                uint256 const minterOfferIndex = keylet::nftoffer(minter, env.seq(minter)).key;
                env(token::createOffer(minter, nftID, XRP(0)), txflags(tfSellNFToken));
                env.close();
 
                // buyer creates their offer.  Note: a buy offer can never
                // offer zero.
                uint256 const buyOfferIndex = keylet::nftoffer(buyer, env.seq(buyer)).key;
                env(token::createOffer(buyer, nftID, XRP(1)), token::owner(minter));
                env.close();
 
                auto const minterBalance = env.balance(minter);
                auto const buyerBalance = env.balance(buyer);
                auto const brokerBalance = env.balance(broker);
                auto const issuerBalance = env.balance(issuer);
 
                // Broker charges a 0.75 XRP brokerFee.
                env(token::brokerOffers(broker, buyOfferIndex, minterOfferIndex),
                    token::brokerFee(XRP(0.75)));
                env.close();
 
                // Note that, with a 50% transfer fee, issuer gets 1/2 of what's
                // left _after_ broker takes their fee.  minter gets the
                // remainder after both broker and minter take their cuts
                BEAST_EXPECT(env.balance(minter) == minterBalance + XRP(0.125));
                BEAST_EXPECT(env.balance(buyer) == buyerBalance - XRP(1));
                BEAST_EXPECT(env.balance(broker) == brokerBalance + XRP(0.75) - baseFee);
                BEAST_EXPECT(env.balance(issuer) == issuerBalance + XRP(0.125));
 
                // Burn the NFT so the next test starts with a clean state.
                env(token::burn(buyer, nftID));
                env.close();
            }
 
            // Lambda to set the balance of all passed in accounts to
            // gwXAU(amount).
            auto setXAUBalance =
                [this, &gw, &gwXAU, &env](
                    std::initializer_list<std::reference_wrapper<Account const>> accounts,
                    int amount,
                    int line) {
                    for (Account const& acct : accounts)
                    {
                        auto const xauAmt = gwXAU(amount);
                        auto const balance = env.balance(acct, gwXAU);
                        if (balance < xauAmt)
                        {
                            env(pay(gw, acct, xauAmt - balance));
                            env.close();
                        }
                        else if (balance > xauAmt)
                        {
                            env(pay(acct, gw, balance - xauAmt));
                            env.close();
                        }
                        if (env.balance(acct, gwXAU) != xauAmt)
                        {
                            std::stringstream ss;
                            ss << "Unable to set " << acct.human() << " account balance to gwXAU("
                               << amount << ")";
                            this->fail(ss.str(), __FILE__, line);
                        }
                    }
                };
 
            // The buyer and seller have identical amounts and there is no
            // transfer fee.
            {
                checkOwnerCountIsOne({issuer, minter, buyer, broker}, __LINE__);
                setXAUBalance({issuer, minter, buyer, broker}, 1000, __LINE__);
 
                uint256 const nftID = mintNFT();
 
                // minter creates their offer.
                uint256 const minterOfferIndex = keylet::nftoffer(minter, env.seq(minter)).key;
                env(token::createOffer(minter, nftID, gwXAU(1000)), txflags(tfSellNFToken));
                env.close();
 
                {
                    // buyer creates an offer for more XAU than they currently
                    // own.
                    uint256 const buyOfferIndex = keylet::nftoffer(buyer, env.seq(buyer)).key;
                    env(token::createOffer(buyer, nftID, gwXAU(1001)), token::owner(minter));
                    env.close();
 
                    // broker attempts to broker the offers but cannot.
                    env(token::brokerOffers(broker, buyOfferIndex, minterOfferIndex),
                        ter(tecINSUFFICIENT_FUNDS));
                    env.close();
 
                    // Cancel buyer's bad offer so the next test starts in a
                    // clean state.
                    env(token::cancelOffer(buyer, {buyOfferIndex}));
                    env.close();
                }
                {
                    // buyer creates an offer for less that what minter is
                    // asking.
                    uint256 const buyOfferIndex = keylet::nftoffer(buyer, env.seq(buyer)).key;
                    env(token::createOffer(buyer, nftID, gwXAU(999)), token::owner(minter));
                    env.close();
 
                    // broker attempts to broker the offers but cannot.
                    env(token::brokerOffers(broker, buyOfferIndex, minterOfferIndex),
                        ter(tecINSUFFICIENT_PAYMENT));
                    env.close();
 
                    // Cancel buyer's bad offer so the next test starts in a
                    // clean state.
                    env(token::cancelOffer(buyer, {buyOfferIndex}));
                    env.close();
                }
 
                // buyer creates a large enough offer.
                uint256 const buyOfferIndex = keylet::nftoffer(buyer, env.seq(buyer)).key;
                env(token::createOffer(buyer, nftID, gwXAU(1000)), token::owner(minter));
                env.close();
 
                // Broker attempts to charge a brokerFee but cannot.
                env(token::brokerOffers(broker, buyOfferIndex, minterOfferIndex),
                    token::brokerFee(gwXAU(0.1)),
                    ter(tecINSUFFICIENT_PAYMENT));
                env.close();
 
                // broker charges no brokerFee and succeeds.
                env(token::brokerOffers(broker, buyOfferIndex, minterOfferIndex));
                env.close();
 
                BEAST_EXPECT(ownerCount(env, issuer) == 1);
                BEAST_EXPECT(ownerCount(env, minter) == 1);
                BEAST_EXPECT(ownerCount(env, buyer) == 2);
                BEAST_EXPECT(ownerCount(env, broker) == 1);
                BEAST_EXPECT(env.balance(issuer, gwXAU) == gwXAU(1000));
                BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(2000));
                BEAST_EXPECT(env.balance(buyer, gwXAU) == gwXAU(0));
                BEAST_EXPECT(env.balance(broker, gwXAU) == gwXAU(1000));
 
                // Burn the NFT so the next test starts with a clean state.
                env(token::burn(buyer, nftID));
                env.close();
            }
 
            // seller offers more than buyer is asking.
            // There are both transfer and broker fees.
            {
                checkOwnerCountIsOne({issuer, minter, buyer, broker}, __LINE__);
                setXAUBalance({issuer, minter, buyer, broker}, 1000, __LINE__);
 
                uint256 const nftID = mintNFT(maxTransferFee);
 
                // minter creates their offer.
                uint256 const minterOfferIndex = keylet::nftoffer(minter, env.seq(minter)).key;
                env(token::createOffer(minter, nftID, gwXAU(900)), txflags(tfSellNFToken));
                env.close();
                {
                    // buyer creates an offer for more XAU than they currently
                    // own.
                    uint256 const buyOfferIndex = keylet::nftoffer(buyer, env.seq(buyer)).key;
                    env(token::createOffer(buyer, nftID, gwXAU(1001)), token::owner(minter));
                    env.close();
 
                    // broker attempts to broker the offers but cannot.
                    env(token::brokerOffers(broker, buyOfferIndex, minterOfferIndex),
                        ter(tecINSUFFICIENT_FUNDS));
                    env.close();
 
                    // Cancel buyer's bad offer so the next test starts in a
                    // clean state.
                    env(token::cancelOffer(buyer, {buyOfferIndex}));
                    env.close();
                }
                {
                    // buyer creates an offer for less that what minter is
                    // asking.
                    uint256 const buyOfferIndex = keylet::nftoffer(buyer, env.seq(buyer)).key;
                    env(token::createOffer(buyer, nftID, gwXAU(899)), token::owner(minter));
                    env.close();
 
                    // broker attempts to broker the offers but cannot.
                    env(token::brokerOffers(broker, buyOfferIndex, minterOfferIndex),
                        ter(tecINSUFFICIENT_PAYMENT));
                    env.close();
 
                    // Cancel buyer's bad offer so the next test starts in a
                    // clean state.
                    env(token::cancelOffer(buyer, {buyOfferIndex}));
                    env.close();
                }
                // buyer creates a large enough offer.
                uint256 const buyOfferIndex = keylet::nftoffer(buyer, env.seq(buyer)).key;
                env(token::createOffer(buyer, nftID, gwXAU(1000)), token::owner(minter));
                env.close();
 
                // Broker attempts to charge a brokerFee larger than the
                // difference between the two offers but cannot.
                env(token::brokerOffers(broker, buyOfferIndex, minterOfferIndex),
                    token::brokerFee(gwXAU(101)),
                    ter(tecINSUFFICIENT_PAYMENT));
                env.close();
 
                // broker charges the full difference between the two offers and
                // succeeds.
                env(token::brokerOffers(broker, buyOfferIndex, minterOfferIndex),
                    token::brokerFee(gwXAU(100)));
                env.close();
 
                BEAST_EXPECT(ownerCount(env, issuer) == 1);
                BEAST_EXPECT(ownerCount(env, minter) == 1);
                BEAST_EXPECT(ownerCount(env, buyer) == 2);
                BEAST_EXPECT(ownerCount(env, broker) == 1);
                BEAST_EXPECT(env.balance(issuer, gwXAU) == gwXAU(1450));
                BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(1450));
                BEAST_EXPECT(env.balance(buyer, gwXAU) == gwXAU(0));
                BEAST_EXPECT(env.balance(broker, gwXAU) == gwXAU(1100));
 
                // Burn the NFT so the next test starts with a clean state.
                env(token::burn(buyer, nftID));
                env.close();
            }
            // seller offers more than buyer is asking.
            // There are both transfer and broker fees, but broker takes less
            // than the maximum.
            {
                checkOwnerCountIsOne({issuer, minter, buyer, broker}, __LINE__);
                setXAUBalance({issuer, minter, buyer, broker}, 1000, __LINE__);
 
                uint256 const nftID = mintNFT(maxTransferFee / 2);  // 25%
 
                // minter creates their offer.
                uint256 const minterOfferIndex = keylet::nftoffer(minter, env.seq(minter)).key;
                env(token::createOffer(minter, nftID, gwXAU(900)), txflags(tfSellNFToken));
                env.close();
 
                // buyer creates a large enough offer.
                uint256 const buyOfferIndex = keylet::nftoffer(buyer, env.seq(buyer)).key;
                env(token::createOffer(buyer, nftID, gwXAU(1000)), token::owner(minter));
                env.close();
 
                // broker charges half difference between the two offers and
                // succeeds.  25% of the remaining difference goes to issuer.
                // The rest goes to minter.
                env(token::brokerOffers(broker, buyOfferIndex, minterOfferIndex),
                    token::brokerFee(gwXAU(50)));
                env.close();
 
                BEAST_EXPECT(ownerCount(env, issuer) == 1);
                BEAST_EXPECT(ownerCount(env, minter) == 1);
                BEAST_EXPECT(ownerCount(env, buyer) == 2);
                BEAST_EXPECT(ownerCount(env, broker) == 1);
                BEAST_EXPECT(env.balance(issuer, gwXAU) == gwXAU(1237.5));
                BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(1712.5));
                BEAST_EXPECT(env.balance(buyer, gwXAU) == gwXAU(0));
                BEAST_EXPECT(env.balance(broker, gwXAU) == gwXAU(1050));
 
                // Burn the NFT so the next test starts with a clean state.
                env(token::burn(buyer, nftID));
                env.close();
            }
            // Broker has a balance less than the seller offer
            {
                checkOwnerCountIsOne({issuer, minter, buyer, broker}, __LINE__);
                setXAUBalance({issuer, minter, buyer}, 1000, __LINE__);
                setXAUBalance({broker}, 500, __LINE__);
                uint256 const nftID = mintNFT(maxTransferFee / 2);  // 25%
 
                // minter creates their offer.
                uint256 const minterOfferIndex = keylet::nftoffer(minter, env.seq(minter)).key;
                env(token::createOffer(minter, nftID, gwXAU(900)), txflags(tfSellNFToken));
                env.close();
 
                // buyer creates a large enough offer.
                uint256 const buyOfferIndex = keylet::nftoffer(buyer, env.seq(buyer)).key;
                env(token::createOffer(buyer, nftID, gwXAU(1000)), token::owner(minter));
                env.close();
 
                env(token::brokerOffers(broker, buyOfferIndex, minterOfferIndex),
                    token::brokerFee(gwXAU(50)));
                env.close();
                BEAST_EXPECT(ownerCount(env, issuer) == 1);
                BEAST_EXPECT(ownerCount(env, minter) == 1);
                BEAST_EXPECT(ownerCount(env, buyer) == 2);
                BEAST_EXPECT(ownerCount(env, broker) == 1);
                BEAST_EXPECT(env.balance(issuer, gwXAU) == gwXAU(1237.5));
                BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(1712.5));
                BEAST_EXPECT(env.balance(buyer, gwXAU) == gwXAU(0));
                BEAST_EXPECT(env.balance(broker, gwXAU) == gwXAU(550));
 
                // Burn the NFT so the next test starts with a clean state.
                env(token::burn(buyer, nftID));
                env.close();
            }
        }
    }
 
    void
    testNFTokenOfferOwner(FeatureBitset features)
    {
        // Verify the Owner field of an offer behaves as expected.
        testcase("NFToken offer owner");
 
        using namespace test::jtx;
 
        Env env{*this, features};
 
        Account const issuer{"issuer"};
        Account const buyer1{"buyer1"};
        Account const buyer2{"buyer2"};
        env.fund(XRP(10000), issuer, buyer1, buyer2);
        env.close();
 
        // issuer creates an NFT.
        uint256 const nftId{token::getNextID(env, issuer, 0u, tfTransferable)};
        env(token::mint(issuer, 0u), txflags(tfTransferable));
        env.close();
 
        // Prove that issuer now owns nftId.
        BEAST_EXPECT(nftCount(env, issuer) == 1);
        BEAST_EXPECT(nftCount(env, buyer1) == 0);
        BEAST_EXPECT(nftCount(env, buyer2) == 0);
 
        // Both buyer1 and buyer2 create buy offers for nftId.
        uint256 const buyer1OfferIndex = keylet::nftoffer(buyer1, env.seq(buyer1)).key;
        env(token::createOffer(buyer1, nftId, XRP(100)), token::owner(issuer));
        uint256 const buyer2OfferIndex = keylet::nftoffer(buyer2, env.seq(buyer2)).key;
        env(token::createOffer(buyer2, nftId, XRP(100)), token::owner(issuer));
        env.close();
 
        // Lambda that counts the number of buy offers for a given NFT.
        auto nftBuyOfferCount = [&env](uint256 const& nftId) -> std::size_t {
            // We know that in this case not very many offers will be
            // returned, so we skip the marker stuff.
            Json::Value params;
            params[jss::nft_id] = to_string(nftId);
            Json::Value buyOffers = env.rpc("json", "nft_buy_offers", to_string(params));
 
            if (buyOffers.isMember(jss::result) && buyOffers[jss::result].isMember(jss::offers))
                return buyOffers[jss::result][jss::offers].size();
 
            return 0;
        };
 
        // Show there are two buy offers for nftId.
        BEAST_EXPECT(nftBuyOfferCount(nftId) == 2);
 
        // issuer accepts buyer1's offer.
        env(token::acceptBuyOffer(issuer, buyer1OfferIndex));
        env.close();
 
        // Prove that buyer1 now owns nftId.
        BEAST_EXPECT(nftCount(env, issuer) == 0);
        BEAST_EXPECT(nftCount(env, buyer1) == 1);
        BEAST_EXPECT(nftCount(env, buyer2) == 0);
 
        // buyer1's offer was consumed, but buyer2's offer is still in the
        // ledger.
        BEAST_EXPECT(nftBuyOfferCount(nftId) == 1);
 
        // buyer1 can now accept buyer2's offer, even though buyer2's
        // NFTokenCreateOffer transaction specified the NFT Owner as issuer.
        env(token::acceptBuyOffer(buyer1, buyer2OfferIndex));
        env.close();
 
        // Prove that buyer2 now owns nftId.
        BEAST_EXPECT(nftCount(env, issuer) == 0);
        BEAST_EXPECT(nftCount(env, buyer1) == 0);
        BEAST_EXPECT(nftCount(env, buyer2) == 1);
 
        // All of the NFTokenOffers are now consumed.
        BEAST_EXPECT(nftBuyOfferCount(nftId) == 0);
    }
 
    void
    testNFTokenWithTickets(FeatureBitset features)
    {
        // Make sure all NFToken transactions work with tickets.
        testcase("NFToken transactions with tickets");
 
        using namespace test::jtx;
 
        Env env{*this, features};
 
        Account const issuer{"issuer"};
        Account const buyer{"buyer"};
        env.fund(XRP(10000), issuer, buyer);
        env.close();
 
        // issuer and buyer grab enough tickets for all of the following
        // transactions.  Note that once the tickets are acquired issuer's
        // and buyer's account sequence numbers should not advance.
        std::uint32_t issuerTicketSeq{env.seq(issuer) + 1};
        env(ticket::create(issuer, 10));
        env.close();
        std::uint32_t const issuerSeq{env.seq(issuer)};
        BEAST_EXPECT(ticketCount(env, issuer) == 10);
 
        std::uint32_t buyerTicketSeq{env.seq(buyer) + 1};
        env(ticket::create(buyer, 10));
        env.close();
        std::uint32_t const buyerSeq{env.seq(buyer)};
        BEAST_EXPECT(ticketCount(env, buyer) == 10);
 
        // NFTokenMint
        BEAST_EXPECT(ownerCount(env, issuer) == 10);
        uint256 const nftId{token::getNextID(env, issuer, 0u, tfTransferable)};
        env(token::mint(issuer, 0u), txflags(tfTransferable), ticket::use(issuerTicketSeq++));
        env.close();
        BEAST_EXPECT(ownerCount(env, issuer) == 10);
        BEAST_EXPECT(ticketCount(env, issuer) == 9);
 
        // NFTokenCreateOffer
        BEAST_EXPECT(ownerCount(env, buyer) == 10);
        uint256 const offerIndex0 = keylet::nftoffer(buyer, buyerTicketSeq).key;
        env(token::createOffer(buyer, nftId, XRP(1)),
            token::owner(issuer),
            ticket::use(buyerTicketSeq++));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 10);
        BEAST_EXPECT(ticketCount(env, buyer) == 9);
 
        // NFTokenCancelOffer
        env(token::cancelOffer(buyer, {offerIndex0}), ticket::use(buyerTicketSeq++));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 8);
        BEAST_EXPECT(ticketCount(env, buyer) == 8);
 
        // NFTokenCreateOffer.  buyer tries again.
        uint256 const offerIndex1 = keylet::nftoffer(buyer, buyerTicketSeq).key;
        env(token::createOffer(buyer, nftId, XRP(2)),
            token::owner(issuer),
            ticket::use(buyerTicketSeq++));
        env.close();
        BEAST_EXPECT(ownerCount(env, buyer) == 8);
        BEAST_EXPECT(ticketCount(env, buyer) == 7);
 
        // NFTokenAcceptOffer.  issuer accepts buyer's offer.
        env(token::acceptBuyOffer(issuer, offerIndex1), ticket::use(issuerTicketSeq++));
        env.close();
        BEAST_EXPECT(ownerCount(env, issuer) == 8);
        BEAST_EXPECT(ownerCount(env, buyer) == 8);
        BEAST_EXPECT(ticketCount(env, issuer) == 8);
 
        // NFTokenBurn.  buyer burns the token they just bought.
        env(token::burn(buyer, nftId), ticket::use(buyerTicketSeq++));
        env.close();
        BEAST_EXPECT(ownerCount(env, issuer) == 8);
        BEAST_EXPECT(ownerCount(env, buyer) == 6);
        BEAST_EXPECT(ticketCount(env, buyer) == 6);
 
        // Verify that the account sequence numbers did not advance.
        BEAST_EXPECT(env.seq(issuer) == issuerSeq);
        BEAST_EXPECT(env.seq(buyer) == buyerSeq);
    }
 
    void
    testNFTokenDeleteAccount(FeatureBitset features)
    {
        // Account deletion rules with NFTs:
        //  1. An account holding one or more NFT offers may be deleted.
        //  2. An NFT issuer with any NFTs they have issued still in the
        //     ledger may not be deleted.
        //  3. An account holding one or more NFTs may not be deleted.
        testcase("NFToken delete account");
 
        using namespace test::jtx;
 
        Env env{*this, features};
 
        Account const issuer{"issuer"};
        Account const minter{"minter"};
        Account const becky{"becky"};
        Account const carla{"carla"};
        Account const daria{"daria"};
 
        env.fund(XRP(10000), issuer, minter, becky, carla, daria);
        env.close();
 
        // Allow enough ledgers to pass so any of these accounts can be deleted.
        for (int i = 0; i < 300; ++i)
            env.close();
 
        env(token::setMinter(issuer, minter));
        env.close();
 
        uint256 const nftId{token::getNextID(env, issuer, 0u, tfTransferable)};
        env(token::mint(minter, 0u), token::issuer(issuer), txflags(tfTransferable));
        env.close();
 
        // At the moment issuer and minter cannot delete themselves.
        //  o issuer has an issued NFT in the ledger.
        //  o minter owns an NFT.
        env(acctdelete(issuer, daria), fee(XRP(50)), ter(tecHAS_OBLIGATIONS));
        env(acctdelete(minter, daria), fee(XRP(50)), ter(tecHAS_OBLIGATIONS));
        env.close();
 
        // Let enough ledgers pass so the account delete transactions are
        // not retried.
        for (int i = 0; i < 15; ++i)
            env.close();
 
        // becky and carla create offers for minter's NFT.
        env(token::createOffer(becky, nftId, XRP(2)), token::owner(minter));
        env.close();
 
        uint256 const carlaOfferIndex = keylet::nftoffer(carla, env.seq(carla)).key;
        env(token::createOffer(carla, nftId, XRP(3)), token::owner(minter));
        env.close();
 
        // It should be possible for becky to delete herself, even though
        // becky has an active NFT offer.
        env(acctdelete(becky, daria), fee(XRP(50)));
        env.close();
 
        // minter accepts carla's offer.
        env(token::acceptBuyOffer(minter, carlaOfferIndex));
        env.close();
 
        // Now it should be possible for minter to delete themselves since
        // they no longer own an NFT.
        env(acctdelete(minter, daria), fee(XRP(50)));
        env.close();
 
        // 1. issuer cannot delete themselves because they issued an NFT that
        //    is still in the ledger.
        // 2. carla owns an NFT, so she cannot delete herself.
        env(acctdelete(issuer, daria), fee(XRP(50)), ter(tecHAS_OBLIGATIONS));
        env(acctdelete(carla, daria), fee(XRP(50)), ter(tecHAS_OBLIGATIONS));
        env.close();
 
        // Let enough ledgers pass so the account delete transactions are
        // not retried.
        for (int i = 0; i < 15; ++i)
            env.close();
 
        // carla burns her NFT.  Since issuer's NFT is no longer in the
        // ledger, both issuer and carla can delete themselves.
        env(token::burn(carla, nftId));
        env.close();
 
        env(acctdelete(issuer, daria), fee(XRP(50)));
        env(acctdelete(carla, daria), fee(XRP(50)));
        env.close();
    }
 
    void
    testNftXxxOffers(FeatureBitset features)
    {
        testcase("nft_buy_offers and nft_sell_offers");
 
        // The default limit on returned NFToken offers is 250, so we need
        // to produce more than 250 offers of each kind in order to exercise
        // the marker.
 
        // Fortunately there's nothing in the rules that says an account
        // can't hold more than one offer for the same NFT.  So we only
        // need two accounts to generate the necessary offers.
        using namespace test::jtx;
 
        Env env{*this, features};
 
        Account const issuer{"issuer"};
        Account const buyer{"buyer"};
 
        // A lot of offers requires a lot for reserve.
        env.fund(XRP(1000000), issuer, buyer);
        env.close();
 
        // Create an NFT that we'll make offers for.
        uint256 const nftID{token::getNextID(env, issuer, 0u, tfTransferable)};
        env(token::mint(issuer, 0), txflags(tfTransferable));
        env.close();
 
        // A lambda that validates nft_XXX_offers query responses.
        auto checkOffers = [this, &env, &nftID](
                               char const* request,
                               int expectCount,
                               int expectMarkerCount,
                               int line) {
            int markerCount = 0;
            Json::Value allOffers(Json::arrayValue);
            std::string marker;
 
            // The do/while collects results until no marker is returned.
            do
            {
                Json::Value nftOffers = [&env, &nftID, &request, &marker]() {
                    Json::Value params;
                    params[jss::nft_id] = to_string(nftID);
 
                    if (!marker.empty())
                        params[jss::marker] = marker;
                    return env.rpc("json", request, to_string(params));
                }();
 
                // If there are no offers for the NFT we get an error
                if (expectCount == 0)
                {
                    if (expect(
                            nftOffers.isMember(jss::result), "expected \"result\"", __FILE__, line))
                    {
                        if (expect(
                                nftOffers[jss::result].isMember(jss::error),
                                "expected \"error\"",
                                __FILE__,
                                line))
                        {
                            expect(
                                nftOffers[jss::result][jss::error].asString() == "objectNotFound",
                                "expected \"objectNotFound\"",
                                __FILE__,
                                line);
                        }
                    }
                    break;
                }
 
                marker.clear();
                if (expect(nftOffers.isMember(jss::result), "expected \"result\"", __FILE__, line))
                {
                    Json::Value& result = nftOffers[jss::result];
 
                    if (result.isMember(jss::marker))
                    {
                        ++markerCount;
                        marker = result[jss::marker].asString();
                    }
 
                    if (expect(result.isMember(jss::offers), "expected \"offers\"", __FILE__, line))
                    {
                        Json::Value& someOffers = result[jss::offers];
                        for (std::size_t i = 0; i < someOffers.size(); ++i)
                            allOffers.append(someOffers[i]);
                    }
                }
            } while (!marker.empty());
 
            // Verify the contents of allOffers makes sense.
            expect(
                allOffers.size() == expectCount, "Unexpected returned offer count", __FILE__, line);
            expect(markerCount == expectMarkerCount, "Unexpected marker count", __FILE__, line);
            std::optional<int> globalFlags;
            std::set<std::string> offerIndexes;
            std::set<std::string> amounts;
            for (Json::Value const& offer : allOffers)
            {
                // The flags on all found offers should be the same.
                if (!globalFlags)
                    globalFlags = offer[jss::flags].asInt();
 
                expect(
                    *globalFlags == offer[jss::flags].asInt(),
                    "Inconsistent flags returned",
                    __FILE__,
                    line);
 
                // The test conditions should produce unique indexes and
                // amounts for all offers.
                offerIndexes.insert(offer[jss::nft_offer_index].asString());
                amounts.insert(offer[jss::amount].asString());
            }
 
            expect(
                offerIndexes.size() == expectCount, "Duplicate indexes returned?", __FILE__, line);
            expect(amounts.size() == expectCount, "Duplicate amounts returned?", __FILE__, line);
        };
 
        // There are no sell offers.
        checkOffers("nft_sell_offers", 0, 0, __LINE__);
 
        // A lambda that generates sell offers.
        STAmount sellPrice = XRP(0);
        auto makeSellOffers = [&env, &issuer, &nftID, &sellPrice](STAmount const& limit) {
            // Save a little test time by not closing too often.
            int offerCount = 0;
            while (sellPrice < limit)
            {
                sellPrice += XRP(1);
                env(token::createOffer(issuer, nftID, sellPrice), txflags(tfSellNFToken));
                if (++offerCount % 10 == 0)
                    env.close();
            }
            env.close();
        };
 
        // There is one sell offer.
        makeSellOffers(XRP(1));
        checkOffers("nft_sell_offers", 1, 0, __LINE__);
 
        // There are 250 sell offers.
        makeSellOffers(XRP(250));
        checkOffers("nft_sell_offers", 250, 0, __LINE__);
 
        // There are 251 sell offers.
        makeSellOffers(XRP(251));
        checkOffers("nft_sell_offers", 251, 1, __LINE__);
 
        // There are 500 sell offers.
        makeSellOffers(XRP(500));
        checkOffers("nft_sell_offers", 500, 1, __LINE__);
 
        // There are 501 sell offers.
        makeSellOffers(XRP(501));
        checkOffers("nft_sell_offers", 501, 2, __LINE__);
 
        // There are no buy offers.
        checkOffers("nft_buy_offers", 0, 0, __LINE__);
 
        // A lambda that generates buy offers.
        STAmount buyPrice = XRP(0);
        auto makeBuyOffers = [&env, &buyer, &issuer, &nftID, &buyPrice](STAmount const& limit) {
            // Save a little test time by not closing too often.
            int offerCount = 0;
            while (buyPrice < limit)
            {
                buyPrice += XRP(1);
                env(token::createOffer(buyer, nftID, buyPrice), token::owner(issuer));
                if (++offerCount % 10 == 0)
                    env.close();
            }
            env.close();
        };
 
        // There is one buy offer;
        makeBuyOffers(XRP(1));
        checkOffers("nft_buy_offers", 1, 0, __LINE__);
 
        // There are 250 buy offers.
        makeBuyOffers(XRP(250));
        checkOffers("nft_buy_offers", 250, 0, __LINE__);
 
        // There are 251 buy offers.
        makeBuyOffers(XRP(251));
        checkOffers("nft_buy_offers", 251, 1, __LINE__);
 
        // There are 500 buy offers.
        makeBuyOffers(XRP(500));
        checkOffers("nft_buy_offers", 500, 1, __LINE__);
 
        // There are 501 buy offers.
        makeBuyOffers(XRP(501));
        checkOffers("nft_buy_offers", 501, 2, __LINE__);
    }
 
    void
    testNFTokenNegOffer(FeatureBitset features)
    {
        using namespace test::jtx;
 
        testcase("NFTokenNegOffer");
 
        Account const issuer{"issuer"};
        Account const buyer{"buyer"};
        Account const gw{"gw"};
        IOU const gwXAU(gw["XAU"]);
 
        {
            Env env{*this, features};
 
            env.fund(XRP(1000000), issuer, buyer, gw);
            env.close();
 
            env(trust(issuer, gwXAU(2000)));
            env(trust(buyer, gwXAU(2000)));
            env.close();
 
            env(pay(gw, issuer, gwXAU(1000)));
            env(pay(gw, buyer, gwXAU(1000)));
            env.close();
 
            // Create an NFT that we'll make XRP offers for.
            uint256 const nftID0{token::getNextID(env, issuer, 0u, tfTransferable)};
            env(token::mint(issuer, 0), txflags(tfTransferable));
            env.close();
 
            // Create an NFT that we'll make IOU offers for.
            uint256 const nftID1{token::getNextID(env, issuer, 1u, tfTransferable)};
            env(token::mint(issuer, 1), txflags(tfTransferable));
            env.close();
 
            TER const offerCreateTER = temBAD_AMOUNT;
 
            // Make offers with negative amounts for the NFTs
            uint256 const sellNegXrpOfferIndex = keylet::nftoffer(issuer, env.seq(issuer)).key;
            env(token::createOffer(issuer, nftID0, XRP(-2)),
                txflags(tfSellNFToken),
                ter(offerCreateTER));
            env.close();
 
            uint256 const sellNegIouOfferIndex = keylet::nftoffer(issuer, env.seq(issuer)).key;
            env(token::createOffer(issuer, nftID1, gwXAU(-2)),
                txflags(tfSellNFToken),
                ter(offerCreateTER));
            env.close();
 
            uint256 const buyNegXrpOfferIndex = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftID0, XRP(-1)),
                token::owner(issuer),
                ter(offerCreateTER));
            env.close();
 
            uint256 const buyNegIouOfferIndex = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::createOffer(buyer, nftID1, gwXAU(-1)),
                token::owner(issuer),
                ter(offerCreateTER));
            env.close();
 
            {
                // Now try to accept the offers.
                TER const offerAcceptTER = tecOBJECT_NOT_FOUND;
 
                // Sell offers.
                env(token::acceptSellOffer(buyer, sellNegXrpOfferIndex), ter(offerAcceptTER));
                env.close();
                env(token::acceptSellOffer(buyer, sellNegIouOfferIndex), ter(offerAcceptTER));
                env.close();
 
                // Buy offers.
                env(token::acceptBuyOffer(issuer, buyNegXrpOfferIndex), ter(offerAcceptTER));
                env.close();
                env(token::acceptBuyOffer(issuer, buyNegIouOfferIndex), ter(offerAcceptTER));
                env.close();
            }
            {
                TER const offerAcceptTER = tecOBJECT_NOT_FOUND;
 
                // Brokered offers.
                env(token::brokerOffers(gw, buyNegXrpOfferIndex, sellNegXrpOfferIndex),
                    ter(offerAcceptTER));
                env.close();
                env(token::brokerOffers(gw, buyNegIouOfferIndex, sellNegIouOfferIndex),
                    ter(offerAcceptTER));
                env.close();
            }
        }
 
        {
            // Test buy offers with a destination.
            Env env{*this, features};
 
            env.fund(XRP(1000000), issuer, buyer);
 
            // Create an NFT that we'll make offers for.
            uint256 const nftID{token::getNextID(env, issuer, 0u, tfTransferable)};
            env(token::mint(issuer, 0), txflags(tfTransferable));
            env.close();
 
            TER const offerCreateTER = tesSUCCESS;
 
            env(token::createOffer(buyer, nftID, drops(1)),
                token::owner(issuer),
                token::destination(issuer),
                ter(offerCreateTER));
            env.close();
        }
    }
 
    void
    testIOUWithTransferFee(FeatureBitset features)
    {
        using namespace test::jtx;
 
        testcase("Payments with IOU transfer fees");
 
        {
            Env env{*this, features};
 
            Account const minter{"minter"};
            Account const secondarySeller{"seller"};
            Account const buyer{"buyer"};
            Account const gw{"gateway"};
            Account const broker{"broker"};
            IOU const gwXAU(gw["XAU"]);
            IOU const gwXPB(gw["XPB"]);
 
            env.fund(XRP(1000), gw, minter, secondarySeller, buyer, broker);
            env.close();
 
            env(trust(minter, gwXAU(2000)));
            env(trust(secondarySeller, gwXAU(2000)));
            env(trust(broker, gwXAU(10000)));
            env(trust(buyer, gwXAU(2000)));
            env(trust(buyer, gwXPB(2000)));
            env.close();
 
            // The IOU issuer has a 2% transfer rate
            env(rate(gw, 1.02));
            env.close();
 
            auto expectInitialState =
                [this, &env, &buyer, &minter, &secondarySeller, &broker, &gw, &gwXAU, &gwXPB]() {
                    // Buyer should have XAU 1000, XPB 0
                    // Minter should have XAU 0, XPB 0
                    // Secondary seller should have XAU 0, XPB 0
                    // Broker should have XAU 5000, XPB 0
                    BEAST_EXPECT(env.balance(buyer, gwXAU) == gwXAU(1000));
                    BEAST_EXPECT(env.balance(buyer, gwXPB) == gwXPB(0));
                    BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(0));
                    BEAST_EXPECT(env.balance(minter, gwXPB) == gwXPB(0));
                    BEAST_EXPECT(env.balance(secondarySeller, gwXAU) == gwXAU(0));
                    BEAST_EXPECT(env.balance(secondarySeller, gwXPB) == gwXPB(0));
                    BEAST_EXPECT(env.balance(broker, gwXAU) == gwXAU(5000));
                    BEAST_EXPECT(env.balance(broker, gwXPB) == gwXPB(0));
                    BEAST_EXPECT(env.balance(gw, buyer["XAU"]) == gwXAU(-1000));
                    BEAST_EXPECT(env.balance(gw, buyer["XPB"]) == gwXPB(0));
                    BEAST_EXPECT(env.balance(gw, minter["XAU"]) == gwXAU(0));
                    BEAST_EXPECT(env.balance(gw, minter["XPB"]) == gwXPB(0));
                    BEAST_EXPECT(env.balance(gw, secondarySeller["XAU"]) == gwXAU(0));
                    BEAST_EXPECT(env.balance(gw, secondarySeller["XPB"]) == gwXPB(0));
                    BEAST_EXPECT(env.balance(gw, broker["XAU"]) == gwXAU(-5000));
                    BEAST_EXPECT(env.balance(gw, broker["XPB"]) == gwXPB(0));
                };
 
            auto reinitializeTrustLineBalances = [&expectInitialState,
                                                  &env,
                                                  &buyer,
                                                  &minter,
                                                  &secondarySeller,
                                                  &broker,
                                                  &gw,
                                                  &gwXAU,
                                                  &gwXPB]() {
                if (auto const difference = gwXAU(1000) - env.balance(buyer, gwXAU);
                    difference > gwXAU(0))
                    env(pay(gw, buyer, difference));
                if (env.balance(buyer, gwXPB) > gwXPB(0))
                    env(pay(buyer, gw, env.balance(buyer, gwXPB)));
                if (env.balance(minter, gwXAU) > gwXAU(0))
                    env(pay(minter, gw, env.balance(minter, gwXAU)));
                if (env.balance(minter, gwXPB) > gwXPB(0))
                    env(pay(minter, gw, env.balance(minter, gwXPB)));
                if (env.balance(secondarySeller, gwXAU) > gwXAU(0))
                    env(pay(secondarySeller, gw, env.balance(secondarySeller, gwXAU)));
                if (env.balance(secondarySeller, gwXPB) > gwXPB(0))
                    env(pay(secondarySeller, gw, env.balance(secondarySeller, gwXPB)));
                auto brokerDiff = gwXAU(5000) - env.balance(broker, gwXAU);
                if (brokerDiff > gwXAU(0))
                {
                    env(pay(gw, broker, brokerDiff));
                }
                else if (brokerDiff < gwXAU(0))
                {
                    brokerDiff.negate();
                    env(pay(broker, gw, brokerDiff));
                }
                if (env.balance(broker, gwXPB) > gwXPB(0))
                    env(pay(broker, gw, env.balance(broker, gwXPB)));
                env.close();
                expectInitialState();
            };
 
            auto mintNFT = [&env](Account const& minter, int transferFee = 0) {
                uint256 const nftID = token::getNextID(env, minter, 0, tfTransferable, transferFee);
                env(token::mint(minter), token::xferFee(transferFee), txflags(tfTransferable));
                env.close();
                return nftID;
            };
 
            auto createBuyOffer = [&env](
                                      Account const& offerer,
                                      Account const& owner,
                                      uint256 const& nftID,
                                      STAmount const& amount,
                                      std::optional<TER const> const terCode = {}) {
                uint256 const offerID = keylet::nftoffer(offerer, env.seq(offerer)).key;
                env(token::createOffer(offerer, nftID, amount),
                    token::owner(owner),
                    terCode ? ter(*terCode) : ter(static_cast<TER>(tesSUCCESS)));
                env.close();
                return offerID;
            };
 
            auto createSellOffer = [&env](
                                       Account const& offerer,
                                       uint256 const& nftID,
                                       STAmount const& amount,
                                       std::optional<TER const> const terCode = {}) {
                uint256 const offerID = keylet::nftoffer(offerer, env.seq(offerer)).key;
                env(token::createOffer(offerer, nftID, amount),
                    txflags(tfSellNFToken),
                    terCode ? ter(*terCode) : ter(static_cast<TER>(tesSUCCESS)));
                env.close();
                return offerID;
            };
 
            {
                // Buyer attempts to send 100% of their balance of an IOU
                // (sellside)
                reinitializeTrustLineBalances();
                auto const nftID = mintNFT(minter);
                auto const offerID = createSellOffer(minter, nftID, gwXAU(1000));
                TER const sellTER = tecINSUFFICIENT_FUNDS;
                env(token::acceptSellOffer(buyer, offerID), ter(sellTER));
                env.close();
 
                expectInitialState();
            }
            {
                // Buyer attempts to send 100% of their balance of an IOU
                // (buyside)
                reinitializeTrustLineBalances();
                auto const nftID = mintNFT(minter);
                auto const offerID = createBuyOffer(buyer, minter, nftID, gwXAU(1000));
                TER const sellTER = tecINSUFFICIENT_FUNDS;
                env(token::acceptBuyOffer(minter, offerID), ter(sellTER));
                env.close();
 
                expectInitialState();
            }
            {
                // Buyer attempts to send an amount less than 100% of their
                // balance of an IOU, but such that the addition of the transfer
                // fee would be greater than the buyer's balance (sellside)
                reinitializeTrustLineBalances();
                auto const nftID = mintNFT(minter);
                auto const offerID = createSellOffer(minter, nftID, gwXAU(995));
                TER const sellTER = tecINSUFFICIENT_FUNDS;
                env(token::acceptSellOffer(buyer, offerID), ter(sellTER));
                env.close();
 
                expectInitialState();
            }
            {
                // Buyer attempts to send an amount less than 100% of their
                // balance of an IOU, but such that the addition of the transfer
                // fee would be greater than the buyer's balance (buyside)
                reinitializeTrustLineBalances();
                auto const nftID = mintNFT(minter);
                auto const offerID = createBuyOffer(buyer, minter, nftID, gwXAU(995));
                TER const sellTER = tecINSUFFICIENT_FUNDS;
                env(token::acceptBuyOffer(minter, offerID), ter(sellTER));
                env.close();
 
                expectInitialState();
            }
            {
                // Buyer attempts to send an amount less than 100% of their
                // balance of an IOU with a transfer fee, and such that the
                // addition of the transfer fee is still less than their balance
                // (sellside)
                reinitializeTrustLineBalances();
                auto const nftID = mintNFT(minter);
                auto const offerID = createSellOffer(minter, nftID, gwXAU(900));
                env(token::acceptSellOffer(buyer, offerID));
                env.close();
 
                BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(900));
                BEAST_EXPECT(env.balance(buyer, gwXAU) == gwXAU(82));
                BEAST_EXPECT(env.balance(gw, minter["XAU"]) == gwXAU(-900));
                BEAST_EXPECT(env.balance(gw, buyer["XAU"]) == gwXAU(-82));
            }
            {
                // Buyer attempts to send an amount less than 100% of their
                // balance of an IOU with a transfer fee, and such that the
                // addition of the transfer fee is still less than their balance
                // (buyside)
                reinitializeTrustLineBalances();
                auto const nftID = mintNFT(minter);
                auto const offerID = createBuyOffer(buyer, minter, nftID, gwXAU(900));
                env(token::acceptBuyOffer(minter, offerID));
                env.close();
 
                BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(900));
                BEAST_EXPECT(env.balance(buyer, gwXAU) == gwXAU(82));
                BEAST_EXPECT(env.balance(gw, minter["XAU"]) == gwXAU(-900));
                BEAST_EXPECT(env.balance(gw, buyer["XAU"]) == gwXAU(-82));
            }
            {
                // Buyer attempts to send an amount less than 100% of their
                // balance of an IOU with a transfer fee, and such that the
                // addition of the transfer fee is equal than their balance
                // (sellside)
                reinitializeTrustLineBalances();
 
                // pay them an additional XAU 20 to cover transfer rate
                env(pay(gw, buyer, gwXAU(20)));
                env.close();
 
                auto const nftID = mintNFT(minter);
                auto const offerID = createSellOffer(minter, nftID, gwXAU(1000));
                env(token::acceptSellOffer(buyer, offerID));
                env.close();
 
                BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(1000));
                BEAST_EXPECT(env.balance(buyer, gwXAU) == gwXAU(0));
                BEAST_EXPECT(env.balance(gw, minter["XAU"]) == gwXAU(-1000));
                BEAST_EXPECT(env.balance(gw, buyer["XAU"]) == gwXAU(0));
            }
            {
                // Buyer attempts to send an amount less than 100% of their
                // balance of an IOU with a transfer fee, and such that the
                // addition of the transfer fee is equal than their balance
                // (buyside)
                reinitializeTrustLineBalances();
 
                // pay them an additional XAU 20 to cover transfer rate
                env(pay(gw, buyer, gwXAU(20)));
                env.close();
 
                auto const nftID = mintNFT(minter);
                auto const offerID = createBuyOffer(buyer, minter, nftID, gwXAU(1000));
                env(token::acceptBuyOffer(minter, offerID));
                env.close();
 
                BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(1000));
                BEAST_EXPECT(env.balance(buyer, gwXAU) == gwXAU(0));
                BEAST_EXPECT(env.balance(gw, minter["XAU"]) == gwXAU(-1000));
                BEAST_EXPECT(env.balance(gw, buyer["XAU"]) == gwXAU(0));
            }
            {
                // Gateway attempts to buy NFT with their own IOU - no
                // transfer fee is calculated here (sellside)
                reinitializeTrustLineBalances();
 
                auto const nftID = mintNFT(minter);
                auto const offerID = createSellOffer(minter, nftID, gwXAU(1000));
                TER const sellTER = tesSUCCESS;
                env(token::acceptSellOffer(gw, offerID), ter(sellTER));
                env.close();
 
                BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(1000));
                BEAST_EXPECT(env.balance(gw, minter["XAU"]) == gwXAU(-1000));
            }
            {
                // Gateway attempts to buy NFT with their own IOU - no
                // transfer fee is calculated here (buyside)
                reinitializeTrustLineBalances();
 
                auto const nftID = mintNFT(minter);
                TER const offerTER = tesSUCCESS;
                auto const offerID = createBuyOffer(gw, minter, nftID, gwXAU(1000), {offerTER});
                TER const sellTER = tesSUCCESS;
                env(token::acceptBuyOffer(minter, offerID), ter(sellTER));
                env.close();
 
                BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(1000));
                BEAST_EXPECT(env.balance(gw, minter["XAU"]) == gwXAU(-1000));
            }
            {
                // Gateway attempts to buy NFT with their own IOU for more
                // than minter trusts (sellside)
                reinitializeTrustLineBalances();
                auto const nftID = mintNFT(minter);
                auto const offerID = createSellOffer(minter, nftID, gwXAU(5000));
                TER const sellTER = tesSUCCESS;
                env(token::acceptSellOffer(gw, offerID), ter(sellTER));
                env.close();
 
                BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(5000));
                BEAST_EXPECT(env.balance(gw, minter["XAU"]) == gwXAU(-5000));
            }
            {
                // Gateway attempts to buy NFT with their own IOU for more
                // than minter trusts (buyside)
                reinitializeTrustLineBalances();
 
                auto const nftID = mintNFT(minter);
                TER const offerTER = tesSUCCESS;
                auto const offerID = createBuyOffer(gw, minter, nftID, gwXAU(5000), {offerTER});
                TER const sellTER = tesSUCCESS;
                env(token::acceptBuyOffer(minter, offerID), ter(sellTER));
                env.close();
 
                BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(5000));
                BEAST_EXPECT(env.balance(gw, minter["XAU"]) == gwXAU(-5000));
            }
            {
                // Gateway is the NFT minter and attempts to sell NFT for an
                // amount that would be greater than a balance if there were a
                // transfer fee calculated in this transaction. (sellside)
                reinitializeTrustLineBalances();
                auto const nftID = mintNFT(gw);
                auto const offerID = createSellOffer(gw, nftID, gwXAU(1000));
                env(token::acceptSellOffer(buyer, offerID));
                env.close();
 
                BEAST_EXPECT(env.balance(buyer, gwXAU) == gwXAU(0));
                BEAST_EXPECT(env.balance(gw, buyer["XAU"]) == gwXAU(0));
            }
            {
                // Gateway is the NFT minter and attempts to sell NFT for an
                // amount that would be greater than a balance if there were a
                // transfer fee calculated in this transaction. (buyside)
                reinitializeTrustLineBalances();
 
                auto const nftID = mintNFT(gw);
                auto const offerID = createBuyOffer(buyer, gw, nftID, gwXAU(1000));
                env(token::acceptBuyOffer(gw, offerID));
                env.close();
 
                BEAST_EXPECT(env.balance(buyer, gwXAU) == gwXAU(0));
                BEAST_EXPECT(env.balance(gw, buyer["XAU"]) == gwXAU(0));
            }
            {
                // Gateway is the NFT minter and attempts to sell NFT for an
                // amount that is greater than a balance before transfer fees.
                // (sellside)
                reinitializeTrustLineBalances();
                auto const nftID = mintNFT(gw);
                auto const offerID = createSellOffer(gw, nftID, gwXAU(2000));
                env(token::acceptSellOffer(buyer, offerID),
                    ter(static_cast<TER>(tecINSUFFICIENT_FUNDS)));
                env.close();
                expectInitialState();
            }
            {
                // Gateway is the NFT minter and attempts to sell NFT for an
                // amount that is greater than a balance before transfer fees.
                // (buyside)
                reinitializeTrustLineBalances();
                auto const nftID = mintNFT(gw);
                auto const offerID = createBuyOffer(buyer, gw, nftID, gwXAU(2000));
                env(token::acceptBuyOffer(gw, offerID),
                    ter(static_cast<TER>(tecINSUFFICIENT_FUNDS)));
                env.close();
                expectInitialState();
            }
            {
                // Minter attempts to sell the token for XPB 10, which they
                // have no trust line for and buyer has none of (sellside).
                reinitializeTrustLineBalances();
                auto const nftID = mintNFT(minter);
                auto const offerID = createSellOffer(minter, nftID, gwXPB(10));
                env(token::acceptSellOffer(buyer, offerID),
                    ter(static_cast<TER>(tecINSUFFICIENT_FUNDS)));
                env.close();
                expectInitialState();
            }
            {
                // Minter attempts to sell the token for XPB 10, which they
                // have no trust line for and buyer has none of (buyside).
                reinitializeTrustLineBalances();
                auto const nftID = mintNFT(minter);
                auto const offerID = createBuyOffer(
                    buyer, minter, nftID, gwXPB(10), {static_cast<TER>(tecUNFUNDED_OFFER)});
                env(token::acceptBuyOffer(minter, offerID),
                    ter(static_cast<TER>(tecOBJECT_NOT_FOUND)));
                env.close();
                expectInitialState();
            }
            {
                // Minter attempts to sell the token for XPB 10 and the buyer
                // has it but the minter has no trust line. Trust line is
                // created as a result of the tx (sellside).
                reinitializeTrustLineBalances();
                env(pay(gw, buyer, gwXPB(100)));
                env.close();
 
                auto const nftID = mintNFT(minter);
                auto const offerID = createSellOffer(minter, nftID, gwXPB(10));
                env(token::acceptSellOffer(buyer, offerID));
                env.close();
 
                BEAST_EXPECT(env.balance(minter, gwXPB) == gwXPB(10));
                BEAST_EXPECT(env.balance(buyer, gwXPB) == gwXPB(89.8));
                BEAST_EXPECT(env.balance(gw, minter["XPB"]) == gwXPB(-10));
                BEAST_EXPECT(env.balance(gw, buyer["XPB"]) == gwXPB(-89.8));
            }
            {
                // Minter attempts to sell the token for XPB 10 and the buyer
                // has it but the minter has no trust line. Trust line is
                // created as a result of the tx (buyside).
                reinitializeTrustLineBalances();
                env(pay(gw, buyer, gwXPB(100)));
                env.close();
 
                auto const nftID = mintNFT(minter);
                auto const offerID = createBuyOffer(buyer, minter, nftID, gwXPB(10));
                env(token::acceptBuyOffer(minter, offerID));
                env.close();
 
                BEAST_EXPECT(env.balance(minter, gwXPB) == gwXPB(10));
                BEAST_EXPECT(env.balance(buyer, gwXPB) == gwXPB(89.8));
                BEAST_EXPECT(env.balance(gw, minter["XPB"]) == gwXPB(-10));
                BEAST_EXPECT(env.balance(gw, buyer["XPB"]) == gwXPB(-89.8));
            }
            {
                // There is a transfer fee on the NFT and buyer has exact
                // amount (sellside)
                reinitializeTrustLineBalances();
 
                // secondarySeller has to sell it because transfer fees only
                // happen on secondary sales
                auto const nftID = mintNFT(minter, 3000);  // 3%
                auto const primaryOfferID = createSellOffer(minter, nftID, XRP(0));
                env(token::acceptSellOffer(secondarySeller, primaryOfferID));
                env.close();
 
                // now we can do a secondary sale
                auto const offerID = createSellOffer(secondarySeller, nftID, gwXAU(1000));
                TER const sellTER = tecINSUFFICIENT_FUNDS;
                env(token::acceptSellOffer(buyer, offerID), ter(sellTER));
                env.close();
 
                expectInitialState();
            }
            {
                // There is a transfer fee on the NFT and buyer has exact
                // amount (buyside)
                reinitializeTrustLineBalances();
 
                // secondarySeller has to sell it because transfer fees only
                // happen on secondary sales
                auto const nftID = mintNFT(minter, 3000);  // 3%
                auto const primaryOfferID = createSellOffer(minter, nftID, XRP(0));
                env(token::acceptSellOffer(secondarySeller, primaryOfferID));
                env.close();
 
                // now we can do a secondary sale
                auto const offerID = createBuyOffer(buyer, secondarySeller, nftID, gwXAU(1000));
                TER const sellTER = tecINSUFFICIENT_FUNDS;
                env(token::acceptBuyOffer(secondarySeller, offerID), ter(sellTER));
                env.close();
 
                expectInitialState();
            }
            {
                // There is a transfer fee on the NFT and buyer has enough
                // (sellside)
                reinitializeTrustLineBalances();
 
                // secondarySeller has to sell it because transfer fees only
                // happen on secondary sales
                auto const nftID = mintNFT(minter, 3000);  // 3%
                auto const primaryOfferID = createSellOffer(minter, nftID, XRP(0));
                env(token::acceptSellOffer(secondarySeller, primaryOfferID));
                env.close();
 
                // now we can do a secondary sale
                auto const offerID = createSellOffer(secondarySeller, nftID, gwXAU(900));
                env(token::acceptSellOffer(buyer, offerID));
                env.close();
 
                BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(27));
                BEAST_EXPECT(env.balance(secondarySeller, gwXAU) == gwXAU(873));
                BEAST_EXPECT(env.balance(buyer, gwXAU) == gwXAU(82));
                BEAST_EXPECT(env.balance(gw, minter["XAU"]) == gwXAU(-27));
                BEAST_EXPECT(env.balance(gw, secondarySeller["XAU"]) == gwXAU(-873));
                BEAST_EXPECT(env.balance(gw, buyer["XAU"]) == gwXAU(-82));
            }
            {
                // There is a transfer fee on the NFT and buyer has enough
                // (buyside)
                reinitializeTrustLineBalances();
 
                // secondarySeller has to sell it because transfer fees only
                // happen on secondary sales
                auto const nftID = mintNFT(minter, 3000);  // 3%
                auto const primaryOfferID = createSellOffer(minter, nftID, XRP(0));
                env(token::acceptSellOffer(secondarySeller, primaryOfferID));
                env.close();
 
                // now we can do a secondary sale
                auto const offerID = createBuyOffer(buyer, secondarySeller, nftID, gwXAU(900));
                env(token::acceptBuyOffer(secondarySeller, offerID));
                env.close();
 
                // receives 3% of 900 - 27
                BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(27));
                // receives 97% of 900 - 873
                BEAST_EXPECT(env.balance(secondarySeller, gwXAU) == gwXAU(873));
                // pays 900 plus 2% transfer fee on XAU - 918
                BEAST_EXPECT(env.balance(buyer, gwXAU) == gwXAU(82));
                BEAST_EXPECT(env.balance(gw, minter["XAU"]) == gwXAU(-27));
                BEAST_EXPECT(env.balance(gw, secondarySeller["XAU"]) == gwXAU(-873));
                BEAST_EXPECT(env.balance(gw, buyer["XAU"]) == gwXAU(-82));
            }
            {
                // There is a broker fee on the NFT. XAU transfer fee is only
                // calculated from the buyer's output, not deducted from
                // broker fee.
                //
                // For a payment of 500 with a 2% IOU transfee fee and 100
                // broker fee:
                //
                // A) Total sale amount + IOU transfer fee is paid by buyer
                //      (Buyer pays (1.02 * 500) = 510)
                // B) GW receives the additional IOU transfer fee
                //      (GW receives 10 from buyer calculated above)
                // C) Broker receives broker fee (no IOU transfer fee)
                //      (Broker receives 100 from buyer)
                // D) Seller receives balance (no IOU transfer fee)
                //      (Seller receives (510 - 10 - 100) = 400)
                reinitializeTrustLineBalances();
 
                auto const nftID = mintNFT(minter);
                auto const sellOffer = createSellOffer(minter, nftID, gwXAU(300));
                auto const buyOffer = createBuyOffer(buyer, minter, nftID, gwXAU(500));
                env(token::brokerOffers(broker, buyOffer, sellOffer), token::brokerFee(gwXAU(100)));
                env.close();
 
                BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(400));
                BEAST_EXPECT(env.balance(buyer, gwXAU) == gwXAU(490));
                BEAST_EXPECT(env.balance(broker, gwXAU) == gwXAU(5100));
                BEAST_EXPECT(env.balance(gw, minter["XAU"]) == gwXAU(-400));
                BEAST_EXPECT(env.balance(gw, buyer["XAU"]) == gwXAU(-490));
                BEAST_EXPECT(env.balance(gw, broker["XAU"]) == gwXAU(-5100));
            }
            {
                // There is broker and transfer fee on the NFT
                //
                // For a payment of 500 with a 2% IOU transfer fee, 3% NFT
                // transfer fee, and 100 broker fee:
                //
                // A) Total sale amount + IOU transfer fee is paid by buyer
                //      (Buyer pays (1.02 * 500) = 510)
                // B) GW receives the additional IOU transfer fee
                //      (GW receives 10 from buyer calculated above)
                // C) Broker receives broker fee (no IOU transfer fee)
                //      (Broker receives 100 from buyer)
                // D) Minter receives transfer fee (no IOU transfer fee)
                //      (Minter receives 0.03 * (510 - 10 - 100) = 12)
                // E) Seller receives balance (no IOU transfer fee)
                //      (Seller receives (510 - 10 - 100 - 12) = 388)
                reinitializeTrustLineBalances();
 
                // secondarySeller has to sell it because transfer fees only
                // happen on secondary sales
                auto const nftID = mintNFT(minter, 3000);  // 3%
                auto const primaryOfferID = createSellOffer(minter, nftID, XRP(0));
                env(token::acceptSellOffer(secondarySeller, primaryOfferID));
                env.close();
 
                // now we can do a secondary sale
                auto const sellOffer = createSellOffer(secondarySeller, nftID, gwXAU(300));
                auto const buyOffer = createBuyOffer(buyer, secondarySeller, nftID, gwXAU(500));
                env(token::brokerOffers(broker, buyOffer, sellOffer), token::brokerFee(gwXAU(100)));
                env.close();
 
                BEAST_EXPECT(env.balance(minter, gwXAU) == gwXAU(12));
                BEAST_EXPECT(env.balance(buyer, gwXAU) == gwXAU(490));
                BEAST_EXPECT(env.balance(secondarySeller, gwXAU) == gwXAU(388));
                BEAST_EXPECT(env.balance(broker, gwXAU) == gwXAU(5100));
                BEAST_EXPECT(env.balance(gw, minter["XAU"]) == gwXAU(-12));
                BEAST_EXPECT(env.balance(gw, buyer["XAU"]) == gwXAU(-490));
                BEAST_EXPECT(env.balance(gw, secondarySeller["XAU"]) == gwXAU(-388));
                BEAST_EXPECT(env.balance(gw, broker["XAU"]) == gwXAU(-5100));
            }
        }
    }
 
    void
    testBrokeredSaleToSelf(FeatureBitset features)
    {
        // There was a bug that if an account had...
        //
        //  1. An NFToken, and
        //  2. An offer on the ledger to buy that same token, and
        //  3. Also an offer of the ledger to sell that same token,
        //
        // Then someone could broker the two offers.  This would result in
        // the NFToken being bought and returned to the original owner and
        // the broker pocketing the profit.
        //
        testcase("Brokered sale to self");
 
        using namespace test::jtx;
 
        Account const alice{"alice"};
        Account const bob{"bob"};
        Account const broker{"broker"};
 
        Env env{*this, features};
        auto const baseFee = env.current()->fees().base;
        env.fund(XRP(10000), alice, bob, broker);
        env.close();
 
        // For this scenario to occur we need the following steps:
        //
        //  1. alice mints NFT.
        //  2. bob creates a buy offer for it for 5 XRP.
        //  3. alice decides to gift the NFT to bob for 0.
        //     creating a sell offer (hopefully using a destination too)
        //  4. Bob accepts the sell offer, because it is better than
        //     paying 5 XRP.
        //  5. At this point, bob has the NFT and still has their buy
        //     offer from when they did not have the NFT!  This is because
        //     the order book is not cleared when an NFT changes hands.
        //  6. Now that Bob owns the NFT, he cannot create new buy offers.
        //     However he still has one left over from when he did not own
        //     it. He can create new sell offers and does.
        //  7. Now that bob has both a buy and a sell offer for the same NFT,
        //     a broker can sell the NFT that bob owns to bob and pocket the
        //     difference.
        uint256 const nftId{token::getNextID(env, alice, 0u, tfTransferable)};
        env(token::mint(alice, 0u), txflags(tfTransferable));
        env.close();
 
        // Bob creates a buy offer for 5 XRP.  Alice creates a sell offer
        // for 0 XRP.
        uint256 const bobBuyOfferIndex = keylet::nftoffer(bob, env.seq(bob)).key;
        env(token::createOffer(bob, nftId, XRP(5)), token::owner(alice));
 
        uint256 const aliceSellOfferIndex = keylet::nftoffer(alice, env.seq(alice)).key;
        env(token::createOffer(alice, nftId, XRP(0)),
            token::destination(bob),
            txflags(tfSellNFToken));
        env.close();
 
        // bob accepts alice's offer but forgets to remove the old buy offer.
        env(token::acceptSellOffer(bob, aliceSellOfferIndex));
        env.close();
 
        // Note that bob still has a buy offer on the books.
        BEAST_EXPECT(env.le(keylet::nftoffer(bobBuyOfferIndex)));
 
        // Bob creates a sell offer for the gift NFT from alice.
        uint256 const bobSellOfferIndex = keylet::nftoffer(bob, env.seq(bob)).key;
        env(token::createOffer(bob, nftId, XRP(4)), txflags(tfSellNFToken));
        env.close();
 
        // bob now has a buy offer and a sell offer on the books.  A broker
        // spots this and swoops in to make a profit.
        BEAST_EXPECT(nftCount(env, bob) == 1);
        auto const bobPriorBalance = env.balance(bob);
        auto const brokerPriorBalance = env.balance(broker);
        env(token::brokerOffers(broker, bobBuyOfferIndex, bobSellOfferIndex),
            token::brokerFee(XRP(1)),
            ter(tecCANT_ACCEPT_OWN_NFTOKEN_OFFER));
        env.close();
 
        // A tec result was returned, so no state should change other
        // than the broker burning their transaction fee.
        BEAST_EXPECT(nftCount(env, bob) == 1);
        BEAST_EXPECT(env.balance(bob) == bobPriorBalance);
        BEAST_EXPECT(env.balance(broker) == brokerPriorBalance - baseFee);
    }
 
    void
    testNFTokenRemint(FeatureBitset features)
    {
        using namespace test::jtx;
 
        testcase("NFTokenRemint");
 
        // Returns the current ledger sequence
        auto openLedgerSeq = [](Env& env) { return env.current()->seq(); };
 
        // Close the ledger until the ledger sequence is large enough to delete
        // the account (no longer within <Sequence + 256>)
        auto incLgrSeqForAcctDel = [&](Env& env, Account const& acct) {
            int const delta = [&]() -> int {
                if (env.seq(acct) + 255 > openLedgerSeq(env))
                    return env.seq(acct) - openLedgerSeq(env) + 255;
                return 0;
            }();
            BEAST_EXPECT(delta >= 0);
            for (int i = 0; i < delta; ++i)
                env.close();
            BEAST_EXPECT(openLedgerSeq(env) == env.seq(acct) + 255);
        };
 
        // Close the ledger until the ledger sequence is no longer
        // within <FirstNFTokenSequence + MintedNFTokens + 256>.
        auto incLgrSeqForFixNftRemint = [&](Env& env, Account const& acct) {
            int delta = 0;
            auto const deletableLgrSeq = (*env.le(acct))[~sfFirstNFTokenSequence].value_or(0) +
                (*env.le(acct))[sfMintedNFTokens] + 255;
 
            if (deletableLgrSeq > openLedgerSeq(env))
                delta = deletableLgrSeq - openLedgerSeq(env);
 
            BEAST_EXPECT(delta >= 0);
            for (int i = 0; i < delta; ++i)
                env.close();
            BEAST_EXPECT(openLedgerSeq(env) == deletableLgrSeq);
        };
 
        // We check if NFTokenIDs can be duplicated by
        // re-creation of an account
        {
            Env env{*this, features};
            Account const alice("alice");
            Account const becky("becky");
 
            env.fund(XRP(10000), alice, becky);
            env.close();
 
            // alice mint and burn a NFT
            uint256 const prevNFTokenID = token::getNextID(env, alice, 0u);
            env(token::mint(alice));
            env.close();
            env(token::burn(alice, prevNFTokenID));
            env.close();
 
            // alice has minted 1 NFToken
            BEAST_EXPECT((*env.le(alice))[sfMintedNFTokens] == 1);
 
            // Close enough ledgers to delete alice's account
            incLgrSeqForAcctDel(env, alice);
 
            // alice's account is deleted
            Keylet const aliceAcctKey{keylet::account(alice.id())};
            auto const acctDelFee{drops(env.current()->fees().increment)};
            env(acctdelete(alice, becky), fee(acctDelFee));
            env.close();
 
            // alice's account root is gone from the most recently
            // closed ledger and the current ledger.
            BEAST_EXPECT(!env.closed()->exists(aliceAcctKey));
            BEAST_EXPECT(!env.current()->exists(aliceAcctKey));
 
            // Fund alice to re-create her account
            env.fund(XRP(10000), alice);
            env.close();
 
            // alice's account now exists and has minted 0 NFTokens
            BEAST_EXPECT(env.closed()->exists(aliceAcctKey));
            BEAST_EXPECT(env.current()->exists(aliceAcctKey));
            BEAST_EXPECT((*env.le(alice))[sfMintedNFTokens] == 0);
 
            // alice mints a NFT with same params as prevNFTokenID
            uint256 const remintNFTokenID = token::getNextID(env, alice, 0u);
            env(token::mint(alice));
            env.close();
 
            // burn the NFT to make sure alice owns remintNFTokenID
            env(token::burn(alice, remintNFTokenID));
            env.close();
 
            // Check that two NFTs don't have the same ID
            BEAST_EXPECT(remintNFTokenID != prevNFTokenID);
        }
 
        // Test if the issuer account can be deleted after an authorized
        // minter mints and burns a batch of NFTokens.
        {
            Env env{*this, features};
            Account const alice("alice");
            Account const becky("becky");
            Account const minter{"minter"};
 
            env.fund(XRP(10000), alice, becky, minter);
            env.close();
 
            // alice sets minter as her authorized minter
            env(token::setMinter(alice, minter));
            env.close();
 
            // minter mints 500 NFTs for alice
            std::vector<uint256> nftIDs;
            nftIDs.reserve(500);
            for (int i = 0; i < 500; i++)
            {
                uint256 const nftokenID = token::getNextID(env, alice, 0u);
                nftIDs.push_back(nftokenID);
                env(token::mint(minter), token::issuer(alice));
            }
            env.close();
 
            // minter burns 500 NFTs
            for (auto const nftokenID : nftIDs)
            {
                env(token::burn(minter, nftokenID));
            }
            env.close();
 
            incLgrSeqForAcctDel(env, alice);
 
            // Verify that alice's account root is present.
            Keylet const aliceAcctKey{keylet::account(alice.id())};
            BEAST_EXPECT(env.closed()->exists(aliceAcctKey));
            BEAST_EXPECT(env.current()->exists(aliceAcctKey));
 
            auto const acctDelFee{drops(env.current()->fees().increment)};
 
            // alice tries to delete her account, but is unsuccessful.
            // Due to authorized minting, alice's account sequence does not
            // advance while minter mints NFTokens for her.
            // The new account deletion restriction <FirstNFTokenSequence +
            // MintedNFTokens + 256> enabled by this amendment will enforce
            // alice to wait for more ledgers to close before she can
            // delete her account, to prevent duplicate NFTokenIDs
            env(acctdelete(alice, becky), fee(acctDelFee), ter(tecTOO_SOON));
            env.close();
 
            // alice's account is still present
            BEAST_EXPECT(env.current()->exists(aliceAcctKey));
 
            // Close more ledgers until it is no longer within
            // <FirstNFTokenSequence + MintedNFTokens + 256>
            // to be able to delete alice's account
            incLgrSeqForFixNftRemint(env, alice);
 
            // alice's account is deleted
            env(acctdelete(alice, becky), fee(acctDelFee));
            env.close();
 
            // alice's account root is gone from the most recently
            // closed ledger and the current ledger.
            BEAST_EXPECT(!env.closed()->exists(aliceAcctKey));
            BEAST_EXPECT(!env.current()->exists(aliceAcctKey));
 
            // Fund alice to re-create her account
            env.fund(XRP(10000), alice);
            env.close();
 
            // alice's account now exists and has minted 0 NFTokens
            BEAST_EXPECT(env.closed()->exists(aliceAcctKey));
            BEAST_EXPECT(env.current()->exists(aliceAcctKey));
            BEAST_EXPECT((*env.le(alice))[sfMintedNFTokens] == 0);
 
            // alice mints a NFT with same params as the first one before
            // the account delete.
            uint256 const remintNFTokenID = token::getNextID(env, alice, 0u);
            env(token::mint(alice));
            env.close();
 
            // burn the NFT to make sure alice owns remintNFTokenID
            env(token::burn(alice, remintNFTokenID));
            env.close();
 
            // The new NFT minted will not have the same ID
            // as any of the NFTs authorized minter minted
            BEAST_EXPECT(std::find(nftIDs.begin(), nftIDs.end(), remintNFTokenID) == nftIDs.end());
        }
 
        // When an account mints and burns a batch of NFTokens using tickets,
        // see if the account can be deleted.
        {
            Env env{*this, features};
 
            Account const alice{"alice"};
            Account const becky{"becky"};
            env.fund(XRP(10000), alice, becky);
            env.close();
 
            // alice grab enough tickets for all of the following
            // transactions.  Note that once the tickets are acquired alice's
            // account sequence number should not advance.
            std::uint32_t aliceTicketSeq{env.seq(alice) + 1};
            env(ticket::create(alice, 100));
            env.close();
 
            BEAST_EXPECT(ticketCount(env, alice) == 100);
            BEAST_EXPECT(ownerCount(env, alice) == 100);
 
            // alice mints 50 NFTs using tickets
            std::vector<uint256> nftIDs;
            nftIDs.reserve(50);
            for (int i = 0; i < 50; i++)
            {
                nftIDs.push_back(token::getNextID(env, alice, 0u));
                env(token::mint(alice, 0u), ticket::use(aliceTicketSeq++));
                env.close();
            }
 
            // alice burns 50 NFTs using tickets
            for (auto const nftokenID : nftIDs)
            {
                env(token::burn(alice, nftokenID), ticket::use(aliceTicketSeq++));
            }
            env.close();
 
            BEAST_EXPECT(ticketCount(env, alice) == 0);
 
            incLgrSeqForAcctDel(env, alice);
 
            // Verify that alice's account root is present.
            Keylet const aliceAcctKey{keylet::account(alice.id())};
            BEAST_EXPECT(env.closed()->exists(aliceAcctKey));
            BEAST_EXPECT(env.current()->exists(aliceAcctKey));
 
            auto const acctDelFee{drops(env.current()->fees().increment)};
 
            // alice tries to delete her account, but is unsuccessful.
            // Due to authorized minting, alice's account sequence does not
            // advance while minter mints NFTokens for her using tickets.
            // The new account deletion restriction <FirstNFTokenSequence +
            // MintedNFTokens + 256> enabled by this amendment will enforce
            // alice to wait for more ledgers to close before she can
            // delete her account, to prevent duplicate NFTokenIDs
            env(acctdelete(alice, becky), fee(acctDelFee), ter(tecTOO_SOON));
            env.close();
 
            // alice's account is still present
            BEAST_EXPECT(env.current()->exists(aliceAcctKey));
 
            // Close more ledgers until it is no longer within
            // <FirstNFTokenSequence + MintedNFTokens + 256>
            // to be able to delete alice's account
            incLgrSeqForFixNftRemint(env, alice);
 
            // alice's account is deleted
            env(acctdelete(alice, becky), fee(acctDelFee));
            env.close();
 
            // alice's account root is gone from the most recently
            // closed ledger and the current ledger.
            BEAST_EXPECT(!env.closed()->exists(aliceAcctKey));
            BEAST_EXPECT(!env.current()->exists(aliceAcctKey));
 
            // Fund alice to re-create her account
            env.fund(XRP(10000), alice);
            env.close();
 
            // alice's account now exists and has minted 0 NFTokens
            BEAST_EXPECT(env.closed()->exists(aliceAcctKey));
            BEAST_EXPECT(env.current()->exists(aliceAcctKey));
            BEAST_EXPECT((*env.le(alice))[sfMintedNFTokens] == 0);
 
            // alice mints a NFT with same params as the first one before
            // the account delete.
            uint256 const remintNFTokenID = token::getNextID(env, alice, 0u);
            env(token::mint(alice));
            env.close();
 
            // burn the NFT to make sure alice owns remintNFTokenID
            env(token::burn(alice, remintNFTokenID));
            env.close();
 
            // The new NFT minted will not have the same ID
            // as any of the NFTs authorized minter minted using tickets
            BEAST_EXPECT(std::find(nftIDs.begin(), nftIDs.end(), remintNFTokenID) == nftIDs.end());
        }
        // When an authorized minter mints and burns a batch of NFTokens using
        // tickets, issuer's account needs to wait a longer time before it can
        // be deleted.
        // After the issuer's account is re-created and mints a NFT, it should
        // not have the same NFTokenID as the ones authorized minter minted.
        Env env{*this, features};
        Account const alice("alice");
        Account const becky("becky");
        Account const minter{"minter"};
 
        env.fund(XRP(10000), alice, becky, minter);
        env.close();
 
        // alice sets minter as her authorized minter
        env(token::setMinter(alice, minter));
        env.close();
 
        // minter creates 100 tickets
        std::uint32_t minterTicketSeq{env.seq(minter) + 1};
        env(ticket::create(minter, 100));
        env.close();
 
        BEAST_EXPECT(ticketCount(env, minter) == 100);
        BEAST_EXPECT(ownerCount(env, minter) == 100);
 
        // minter mints 50 NFTs for alice using tickets
        std::vector<uint256> nftIDs;
        nftIDs.reserve(50);
        for (int i = 0; i < 50; i++)
        {
            uint256 const nftokenID = token::getNextID(env, alice, 0u);
            nftIDs.push_back(nftokenID);
            env(token::mint(minter), token::issuer(alice), ticket::use(minterTicketSeq++));
        }
        env.close();
 
        // minter burns 50 NFTs using tickets
        for (auto const nftokenID : nftIDs)
        {
            env(token::burn(minter, nftokenID), ticket::use(minterTicketSeq++));
        }
        env.close();
 
        BEAST_EXPECT(ticketCount(env, minter) == 0);
 
        incLgrSeqForAcctDel(env, alice);
 
        // Verify that alice's account root is present.
        Keylet const aliceAcctKey{keylet::account(alice.id())};
        BEAST_EXPECT(env.closed()->exists(aliceAcctKey));
        BEAST_EXPECT(env.current()->exists(aliceAcctKey));
 
        // alice tries to delete her account, but is unsuccessful.
        // Due to authorized minting, alice's account sequence does not
        // advance while minter mints NFTokens for her using tickets.
        // The new account deletion restriction <FirstNFTokenSequence +
        // MintedNFTokens + 256> enabled by this amendment will enforce
        // alice to wait for more ledgers to close before she can delete her
        // account, to prevent duplicate NFTokenIDs
        auto const acctDelFee{drops(env.current()->fees().increment)};
        env(acctdelete(alice, becky), fee(acctDelFee), ter(tecTOO_SOON));
        env.close();
 
        // alice's account is still present
        BEAST_EXPECT(env.current()->exists(aliceAcctKey));
 
        // Close more ledgers until it is no longer within
        // <FirstNFTokenSequence + MintedNFTokens + 256>
        // to be able to delete alice's account
        incLgrSeqForFixNftRemint(env, alice);
 
        // alice's account is deleted
        env(acctdelete(alice, becky), fee(acctDelFee));
        env.close();
 
        // alice's account root is gone from the most recently
        // closed ledger and the current ledger.
        BEAST_EXPECT(!env.closed()->exists(aliceAcctKey));
        BEAST_EXPECT(!env.current()->exists(aliceAcctKey));
 
        // Fund alice to re-create her account
        env.fund(XRP(10000), alice);
        env.close();
 
        // alice's account now exists and has minted 0 NFTokens
        BEAST_EXPECT(env.closed()->exists(aliceAcctKey));
        BEAST_EXPECT(env.current()->exists(aliceAcctKey));
        BEAST_EXPECT((*env.le(alice))[sfMintedNFTokens] == 0);
 
        // The new NFT minted will not have the same ID
        // as any of the NFTs authorized minter minted using tickets
        uint256 const remintNFTokenID = token::getNextID(env, alice, 0u);
        env(token::mint(alice));
        env.close();
 
        // burn the NFT to make sure alice owns remintNFTokenID
        env(token::burn(alice, remintNFTokenID));
        env.close();
 
        // The new NFT minted will not have the same ID
        // as one of NFTs authorized minter minted using tickets
        BEAST_EXPECT(std::find(nftIDs.begin(), nftIDs.end(), remintNFTokenID) == nftIDs.end());
    }
 
    void
    testFeatMintWithOffer(FeatureBitset features)
    {
        testcase("NFTokenMint with Create NFTokenOffer");
 
        using namespace test::jtx;
 
        if (!features[featureNFTokenMintOffer])
        {
            Env env{*this, features};
            Account const alice("alice");
            Account const buyer("buyer");
 
            env.fund(XRP(10000), alice, buyer);
            env.close();
 
            env(token::mint(alice), token::amount(XRP(10000)), ter(temDISABLED));
            env.close();
 
            env(token::mint(alice), token::destination("buyer"), ter(temDISABLED));
            env.close();
 
            env(token::mint(alice), token::expiration(lastClose(env) + 25), ter(temDISABLED));
            env.close();
 
            return;
        }
 
        // The remaining tests assume featureNFTokenMintOffer is enabled.
        {
            Env env{*this, features};
            auto const baseFee = env.current()->fees().base;
            Account const alice("alice");
            Account const buyer{"buyer"};
            Account const gw("gw");
            Account const issuer("issuer");
            Account const minter("minter");
            Account const bob("bob");
            IOU const gwAUD(gw["AUD"]);
 
            env.fund(XRP(10000), alice, buyer, gw, issuer, minter);
            env.close();
 
            {
                // Destination field specified but Amount field not specified
                env(token::mint(alice), token::destination(buyer), ter(temMALFORMED));
                env.close();
                BEAST_EXPECT(ownerCount(env, alice) == 0);
 
                // Expiration field specified but Amount field not specified
                env(token::mint(alice), token::expiration(lastClose(env) + 25), ter(temMALFORMED));
                env.close();
                BEAST_EXPECT(ownerCount(env, buyer) == 0);
            }
 
            {
                // The destination may not be the account submitting the
                // transaction.
                env(token::mint(alice),
                    token::amount(XRP(1000)),
                    token::destination(alice),
                    ter(temMALFORMED));
                env.close();
                BEAST_EXPECT(ownerCount(env, alice) == 0);
 
                // The destination must be an account already established in the
                // ledger.
                env(token::mint(alice),
                    token::amount(XRP(1000)),
                    token::destination(Account("demon")),
                    ter(tecNO_DST));
                env.close();
                BEAST_EXPECT(ownerCount(env, alice) == 0);
            }
 
            {
                // Set a bad expiration.
                env(token::mint(alice),
                    token::amount(XRP(1000)),
                    token::expiration(0),
                    ter(temBAD_EXPIRATION));
                env.close();
                BEAST_EXPECT(ownerCount(env, alice) == 0);
 
                // The new NFTokenOffer may not have passed its expiration time.
                env(token::mint(alice),
                    token::amount(XRP(1000)),
                    token::expiration(lastClose(env)),
                    ter(tecEXPIRED));
                env.close();
                BEAST_EXPECT(ownerCount(env, alice) == 0);
            }
 
            {
                // Set an invalid amount.
                env(token::mint(alice),
                    token::amount(buyer["USD"](1)),
                    txflags(tfOnlyXRP),
                    ter(temBAD_AMOUNT));
                env(token::mint(alice), token::amount(buyer["USD"](0)), ter(temBAD_AMOUNT));
                env.close();
                BEAST_EXPECT(ownerCount(env, alice) == 0);
 
                // Issuer (alice) must have a trust line for the offered funds.
                env(token::mint(alice),
                    token::amount(gwAUD(1000)),
                    txflags(tfTransferable),
                    token::xferFee(10),
                    ter(tecNO_LINE));
                env.close();
                BEAST_EXPECT(ownerCount(env, alice) == 0);
 
                // If the IOU issuer and the NFToken issuer are the same,
                // then that issuer does not need a trust line to accept their
                // fee.
                env(token::mint(gw),
                    token::amount(gwAUD(1000)),
                    txflags(tfTransferable),
                    token::xferFee(10));
                env.close();
 
                // Give alice the needed trust line, but freeze it.
                env(trust(gw, alice["AUD"](999), tfSetFreeze));
                env.close();
 
                // Issuer (alice) must have a trust line for the offered funds
                // and the trust line may not be frozen.
                env(token::mint(alice),
                    token::amount(gwAUD(1000)),
                    txflags(tfTransferable),
                    token::xferFee(10),
                    ter(tecFROZEN));
                env.close();
                BEAST_EXPECT(ownerCount(env, alice) == 0);
 
                // Seller (alice) must have a trust line may not be frozen.
                env(token::mint(alice), token::amount(gwAUD(1000)), ter(tecFROZEN));
                env.close();
                BEAST_EXPECT(ownerCount(env, alice) == 0);
 
                // Unfreeze alice's trustline.
                env(trust(gw, alice["AUD"](999), tfClearFreeze));
                env.close();
            }
 
            {
                // check reserve
                auto const acctReserve = env.current()->fees().reserve;
                auto const incReserve = env.current()->fees().increment;
 
                env.fund(acctReserve + incReserve, bob);
                env.close();
 
                // doesn't have reserve for 2 objects (NFTokenPage, Offer)
                env(token::mint(bob), token::amount(XRP(0)), ter(tecINSUFFICIENT_RESERVE));
                env.close();
 
                // have reserve for NFTokenPage, Offer
                env(pay(env.master, bob, incReserve + drops(baseFee)));
                env.close();
                env(token::mint(bob), token::amount(XRP(0)));
                env.close();
 
                // doesn't have reserve for Offer
                env(pay(env.master, bob, drops(baseFee)));
                env.close();
                env(token::mint(bob), token::amount(XRP(0)), ter(tecINSUFFICIENT_RESERVE));
                env.close();
 
                // have reserve for Offer
                env(pay(env.master, bob, incReserve + drops(baseFee)));
                env.close();
                env(token::mint(bob), token::amount(XRP(0)));
                env.close();
            }
 
            // Amount field specified
            BEAST_EXPECT(ownerCount(env, alice) == 0);
            env(token::mint(alice), token::amount(XRP(10)));
            BEAST_EXPECT(ownerCount(env, alice) == 2);
            env.close();
 
            // Amount field and Destination field, Expiration field specified
            env(token::mint(alice),
                token::amount(XRP(10)),
                token::destination(buyer),
                token::expiration(lastClose(env) + 25));
            env.close();
 
            // With TransferFee field
            env(trust(alice, gwAUD(1000)));
            env.close();
            env(token::mint(alice),
                token::amount(gwAUD(1)),
                token::destination(buyer),
                token::expiration(lastClose(env) + 25),
                txflags(tfTransferable),
                token::xferFee(10));
            env.close();
 
            // Can be canceled by the issuer.
            env(token::mint(alice),
                token::amount(XRP(10)),
                token::destination(buyer),
                token::expiration(lastClose(env) + 25));
            uint256 const offerAliceSellsToBuyer = keylet::nftoffer(alice, env.seq(alice)).key;
            env(token::cancelOffer(alice, {offerAliceSellsToBuyer}));
            env.close();
 
            // Can be canceled by the buyer.
            env(token::mint(buyer),
                token::amount(XRP(10)),
                token::destination(alice),
                token::expiration(lastClose(env) + 25));
            uint256 const offerBuyerSellsToAlice = keylet::nftoffer(buyer, env.seq(buyer)).key;
            env(token::cancelOffer(alice, {offerBuyerSellsToAlice}));
            env.close();
 
            env(token::setMinter(issuer, minter));
            env.close();
 
            // Minter will have offer not issuer
            BEAST_EXPECT(ownerCount(env, minter) == 0);
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            env(token::mint(minter), token::issuer(issuer), token::amount(drops(1)));
            env.close();
            BEAST_EXPECT(ownerCount(env, minter) == 2);
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
        }
 
        Env env{*this, features};
        Account const alice("alice");
 
        env.fund(XRP(1000000), alice);
 
        TER const offerCreateTER = temBAD_AMOUNT;
 
        // Make offers with negative amounts for the NFTs
        env(token::mint(alice), token::amount(XRP(-2)), ter(offerCreateTER));
        env.close();
    }
 
    void
    testTxJsonMetaFields(FeatureBitset features)
    {
        // `nftoken_id` is added in the `tx` response for NFTokenMint and
        // NFTokenAcceptOffer.
        //
        // `nftoken_ids` is added in the `tx` response for NFTokenCancelOffer
        //
        // `offer_id` is added in the `tx` response for NFTokenCreateOffer
        //
        // The values of these fields are dependent on the NFTokenID/OfferID
        // changed in its corresponding transaction. We want to validate each
        // transaction to make sure the synthetic fields hold the right values.
 
        testcase("Test synthetic fields from JSON response");
 
        using namespace test::jtx;
 
        Account const alice{"alice"};
        Account const bob{"bob"};
        Account const broker{"broker"};
 
        Env env{*this, features};
        env.fund(XRP(10000), alice, bob, broker);
        env.close();
 
        // Verify `nftoken_id` value equals to the NFTokenID that was
        // changed in the most recent NFTokenMint or NFTokenAcceptOffer
        // transaction
        auto verifyNFTokenID = [&](uint256 const& actualNftID) {
            // Get the hash for the most recent transaction.
            std::string const txHash{env.tx()->getJson(JsonOptions::none)[jss::hash].asString()};
 
            env.close();
            Json::Value const meta = env.rpc("tx", txHash)[jss::result][jss::meta];
 
            // Expect nftokens_id field
            if (!BEAST_EXPECT(meta.isMember(jss::nftoken_id)))
                return;
 
            // Check the value of NFT ID in the meta with the
            // actual value
            uint256 nftID;
            BEAST_EXPECT(nftID.parseHex(meta[jss::nftoken_id].asString()));
            BEAST_EXPECT(nftID == actualNftID);
        };
 
        // Verify `nftoken_ids` value equals to the NFTokenIDs that were
        // changed in the most recent NFTokenCancelOffer transaction
        auto verifyNFTokenIDsInCancelOffer = [&](std::vector<uint256> actualNftIDs) {
            // Get the hash for the most recent transaction.
            std::string const txHash{env.tx()->getJson(JsonOptions::none)[jss::hash].asString()};
 
            env.close();
            Json::Value const meta = env.rpc("tx", txHash)[jss::result][jss::meta];
 
            // Expect nftokens_ids field and verify the values
            if (!BEAST_EXPECT(meta.isMember(jss::nftoken_ids)))
                return;
 
            // Convert NFT IDs from Json::Value to uint256
            std::vector<uint256> metaIDs;
            std::transform(
                meta[jss::nftoken_ids].begin(),
                meta[jss::nftoken_ids].end(),
                std::back_inserter(metaIDs),
                [this](Json::Value id) {
                    uint256 nftID;
                    BEAST_EXPECT(nftID.parseHex(id.asString()));
                    return nftID;
                });
 
            // Sort both array to prepare for comparison
            std::sort(metaIDs.begin(), metaIDs.end());
            std::sort(actualNftIDs.begin(), actualNftIDs.end());
 
            // Make sure the expect number of NFTs is correct
            BEAST_EXPECT(metaIDs.size() == actualNftIDs.size());
 
            // Check the value of NFT ID in the meta with the
            // actual values
            for (size_t i = 0; i < metaIDs.size(); ++i)
                BEAST_EXPECT(metaIDs[i] == actualNftIDs[i]);
        };
 
        // Verify `offer_id` value equals to the offerID that was
        // changed in the most recent NFTokenCreateOffer tx
        auto verifyNFTokenOfferID = [&](uint256 const& offerID) {
            // Get the hash for the most recent transaction.
            std::string const txHash{env.tx()->getJson(JsonOptions::none)[jss::hash].asString()};
 
            env.close();
            Json::Value const meta = env.rpc("tx", txHash)[jss::result][jss::meta];
 
            // Expect offer_id field and verify the value
            if (!BEAST_EXPECT(meta.isMember(jss::offer_id)))
                return;
 
            uint256 metaOfferID;
            BEAST_EXPECT(metaOfferID.parseHex(meta[jss::offer_id].asString()));
            BEAST_EXPECT(metaOfferID == offerID);
        };
 
        // Check new fields in tx meta when for all NFTtransactions
        {
            // Alice mints 2 NFTs
            // Verify the NFTokenIDs are correct in the NFTokenMint tx meta
            uint256 const nftId1{token::getNextID(env, alice, 0u, tfTransferable)};
            env(token::mint(alice, 0u), txflags(tfTransferable));
            env.close();
            verifyNFTokenID(nftId1);
 
            uint256 const nftId2{token::getNextID(env, alice, 0u, tfTransferable)};
            env(token::mint(alice, 0u), txflags(tfTransferable));
            env.close();
            verifyNFTokenID(nftId2);
 
            // Alice creates one sell offer for each NFT
            // Verify the offer indexes are correct in the NFTokenCreateOffer tx
            // meta
            uint256 const aliceOfferIndex1 = keylet::nftoffer(alice, env.seq(alice)).key;
            env(token::createOffer(alice, nftId1, drops(1)), txflags(tfSellNFToken));
            env.close();
            verifyNFTokenOfferID(aliceOfferIndex1);
 
            uint256 const aliceOfferIndex2 = keylet::nftoffer(alice, env.seq(alice)).key;
            env(token::createOffer(alice, nftId2, drops(1)), txflags(tfSellNFToken));
            env.close();
            verifyNFTokenOfferID(aliceOfferIndex2);
 
            // Alice cancels two offers she created
            // Verify the NFTokenIDs are correct in the NFTokenCancelOffer tx
            // meta
            env(token::cancelOffer(alice, {aliceOfferIndex1, aliceOfferIndex2}));
            env.close();
            verifyNFTokenIDsInCancelOffer({nftId1, nftId2});
 
            // Bobs creates a buy offer for nftId1
            // Verify the offer id is correct in the NFTokenCreateOffer tx meta
            auto const bobBuyOfferIndex = keylet::nftoffer(bob, env.seq(bob)).key;
            env(token::createOffer(bob, nftId1, drops(1)), token::owner(alice));
            env.close();
            verifyNFTokenOfferID(bobBuyOfferIndex);
 
            // Alice accepts bob's buy offer
            // Verify the NFTokenID is correct in the NFTokenAcceptOffer tx meta
            env(token::acceptBuyOffer(alice, bobBuyOfferIndex));
            env.close();
            verifyNFTokenID(nftId1);
        }
 
        // Check `nftoken_ids` in brokered mode
        {
            // Alice mints a NFT
            uint256 const nftId{token::getNextID(env, alice, 0u, tfTransferable)};
            env(token::mint(alice, 0u), txflags(tfTransferable));
            env.close();
            verifyNFTokenID(nftId);
 
            // Alice creates sell offer and set broker as destination
            uint256 const offerAliceToBroker = keylet::nftoffer(alice, env.seq(alice)).key;
            env(token::createOffer(alice, nftId, drops(1)),
                token::destination(broker),
                txflags(tfSellNFToken));
            env.close();
            verifyNFTokenOfferID(offerAliceToBroker);
 
            // Bob creates buy offer
            uint256 const offerBobToBroker = keylet::nftoffer(bob, env.seq(bob)).key;
            env(token::createOffer(bob, nftId, drops(1)), token::owner(alice));
            env.close();
            verifyNFTokenOfferID(offerBobToBroker);
 
            // Check NFTokenID meta for NFTokenAcceptOffer in brokered mode
            env(token::brokerOffers(broker, offerBobToBroker, offerAliceToBroker));
            env.close();
            verifyNFTokenID(nftId);
        }
 
        // Check if there are no duplicate nft id in Cancel transactions where
        // multiple offers are cancelled for the same NFT
        {
            // Alice mints a NFT
            uint256 const nftId{token::getNextID(env, alice, 0u, tfTransferable)};
            env(token::mint(alice, 0u), txflags(tfTransferable));
            env.close();
            verifyNFTokenID(nftId);
 
            // Alice creates 2 sell offers for the same NFT
            uint256 const aliceOfferIndex1 = keylet::nftoffer(alice, env.seq(alice)).key;
            env(token::createOffer(alice, nftId, drops(1)), txflags(tfSellNFToken));
            env.close();
            verifyNFTokenOfferID(aliceOfferIndex1);
 
            uint256 const aliceOfferIndex2 = keylet::nftoffer(alice, env.seq(alice)).key;
            env(token::createOffer(alice, nftId, drops(1)), txflags(tfSellNFToken));
            env.close();
            verifyNFTokenOfferID(aliceOfferIndex2);
 
            // Make sure the metadata only has 1 nft id, since both offers are
            // for the same nft
            env(token::cancelOffer(alice, {aliceOfferIndex1, aliceOfferIndex2}));
            env.close();
            verifyNFTokenIDsInCancelOffer({nftId});
        }
 
        if (features[featureNFTokenMintOffer])
        {
            uint256 const aliceMintWithOfferIndex1 = keylet::nftoffer(alice, env.seq(alice)).key;
            env(token::mint(alice), token::amount(XRP(0)));
            env.close();
            verifyNFTokenOfferID(aliceMintWithOfferIndex1);
        }
    }
 
    void
    testFixNFTokenBuyerReserve(FeatureBitset features)
    {
        testcase("Test buyer reserve when accepting an offer");
 
        using namespace test::jtx;
 
        // Lambda that mints an NFT and then creates a sell offer
        auto mintAndCreateSellOffer =
            [](test::jtx::Env& env, test::jtx::Account const& acct, STAmount const amt) -> uint256 {
            // acct mints a NFT
            uint256 const nftId{token::getNextID(env, acct, 0u, tfTransferable)};
            env(token::mint(acct, 0u), txflags(tfTransferable));
            env.close();
 
            // acct makes an sell offer
            uint256 const sellOfferIndex = keylet::nftoffer(acct, env.seq(acct)).key;
            env(token::createOffer(acct, nftId, amt), txflags(tfSellNFToken));
            env.close();
 
            return sellOfferIndex;
        };
 
        // Test the behaviors when the buyer makes an accept offer, both before
        // and after enabling the amendment. Exercises the precise number of
        // reserve in drops that's required to accept the offer
        {
            Account const alice{"alice"};
            Account const bob{"bob"};
 
            Env env{*this, features};
            auto const acctReserve = env.current()->fees().reserve;
            auto const incReserve = env.current()->fees().increment;
            auto const baseFee = env.current()->fees().base;
 
            env.fund(XRP(10000), alice);
            env.close();
 
            // Bob is funded with minimum XRP reserve
            env.fund(acctReserve, bob);
            env.close();
 
            // alice mints an NFT and create a sell offer for 0 XRP
            auto const sellOfferIndex = mintAndCreateSellOffer(env, alice, XRP(0));
 
            // Bob owns no object
            BEAST_EXPECT(ownerCount(env, bob) == 0);
 
            // Without fixNFTokenReserve amendment, when bob accepts an NFT sell
            // offer, he can get the NFT free of reserve
            if (!features[fixNFTokenReserve])
            {
                // Bob is able to accept the offer
                env(token::acceptSellOffer(bob, sellOfferIndex));
                env.close();
 
                // Bob now owns an extra objects
                BEAST_EXPECT(ownerCount(env, bob) == 1);
 
                // This is the wrong behavior, since Bob should need at least
                // one incremental reserve.
            }
            // With fixNFTokenReserve, bob can no longer accept the offer unless
            // there is enough reserve. A detail to note is that NFTs(sell
            // offer) will not allow one to go below the reserve requirement,
            // because buyer's balance is computed after the transaction fee is
            // deducted. This means that the reserve requirement will be `base
            // fee` drops higher than normal.
            else
            {
                // Bob is not able to accept the offer with only the account
                // reserve (200,000,000 drops)
                env(token::acceptSellOffer(bob, sellOfferIndex), ter(tecINSUFFICIENT_RESERVE));
                env.close();
 
                // after prev transaction, Bob owns `200M - base fee` drops due
                // to burnt tx fee
 
                BEAST_EXPECT(ownerCount(env, bob) == 0);
 
                // Send bob an increment reserve and base fee (to make up for
                // the transaction fee burnt from the prev failed tx) Bob now
                // owns 250,000,000 drops
                env(pay(env.master, bob, incReserve + drops(baseFee)));
                env.close();
 
                // However, this transaction will still fail because the reserve
                // requirement is `base fee` drops higher
                env(token::acceptSellOffer(bob, sellOfferIndex), ter(tecINSUFFICIENT_RESERVE));
                env.close();
 
                // Send bob `base fee * 2` drops
                // Bob now owns `250M + base fee` drops
                env(pay(env.master, bob, drops(baseFee * 2)));
                env.close();
 
                // Bob is now able to accept the offer
                env(token::acceptSellOffer(bob, sellOfferIndex));
                env.close();
 
                BEAST_EXPECT(ownerCount(env, bob) == 1);
            }
        }
 
        // Now exercise the scenario when the buyer accepts
        // many sell offers
        {
            Account const alice{"alice"};
            Account const bob{"bob"};
 
            Env env{*this, features};
            auto const acctReserve = env.current()->fees().reserve;
            auto const incReserve = env.current()->fees().increment;
 
            env.fund(XRP(10000), alice);
            env.close();
 
            env.fund(acctReserve + XRP(1), bob);
            env.close();
 
            if (!features[fixNFTokenReserve])
            {
                // Bob can accept many NFTs without having a single reserve!
                for (size_t i = 0; i < 200; i++)
                {
                    // alice mints an NFT and creates a sell offer for 0 XRP
                    auto const sellOfferIndex = mintAndCreateSellOffer(env, alice, XRP(0));
 
                    // Bob is able to accept the offer
                    env(token::acceptSellOffer(bob, sellOfferIndex));
                    env.close();
                }
            }
            else
            {
                // alice mints the first NFT and creates a sell offer for 0 XRP
                auto const sellOfferIndex1 = mintAndCreateSellOffer(env, alice, XRP(0));
 
                // Bob cannot accept this offer because he doesn't have the
                // reserve for the NFT
                env(token::acceptSellOffer(bob, sellOfferIndex1), ter(tecINSUFFICIENT_RESERVE));
                env.close();
 
                // Give bob enough reserve
                env(pay(env.master, bob, drops(incReserve)));
                env.close();
 
                BEAST_EXPECT(ownerCount(env, bob) == 0);
 
                // Bob now owns his first NFT
                env(token::acceptSellOffer(bob, sellOfferIndex1));
                env.close();
 
                BEAST_EXPECT(ownerCount(env, bob) == 1);
 
                // alice now mints 31 more NFTs and creates an offer for each
                // NFT, then sells to bob
                for (size_t i = 0; i < 31; i++)
                {
                    // alice mints an NFT and creates a sell offer for 0 XRP
                    auto const sellOfferIndex = mintAndCreateSellOffer(env, alice, XRP(0));
 
                    // Bob can accept the offer because the new NFT is stored in
                    // an existing NFTokenPage so no new reserve is required
                    env(token::acceptSellOffer(bob, sellOfferIndex));
                    env.close();
                }
 
                BEAST_EXPECT(ownerCount(env, bob) == 1);
 
                // alice now mints the 33rd NFT and creates an sell offer for 0
                // XRP
                auto const sellOfferIndex33 = mintAndCreateSellOffer(env, alice, XRP(0));
 
                // Bob fails to accept this NFT because he does not have enough
                // reserve for a new NFTokenPage
                env(token::acceptSellOffer(bob, sellOfferIndex33), ter(tecINSUFFICIENT_RESERVE));
                env.close();
 
                // Send bob incremental reserve
                env(pay(env.master, bob, drops(incReserve)));
                env.close();
 
                // Bob now has enough reserve to accept the offer and now
                // owns one more NFTokenPage
                env(token::acceptSellOffer(bob, sellOfferIndex33));
                env.close();
 
                BEAST_EXPECT(ownerCount(env, bob) == 2);
            }
        }
 
        // Test the behavior when the seller accepts a buy offer.
        // The behavior should not change regardless whether fixNFTokenReserve
        // is enabled or not, since the ledger is able to guard against
        // free NFTokenPages when buy offer is accepted. This is merely an
        // additional test to exercise existing offer behavior.
        {
            Account const alice{"alice"};
            Account const bob{"bob"};
 
            Env env{*this, features};
            auto const acctReserve = env.current()->fees().reserve;
            auto const incReserve = env.current()->fees().increment;
            auto const baseFee = env.current()->fees().base;
 
            env.fund(XRP(10000), alice);
            env.close();
 
            // Bob is funded with account reserve + increment reserve + 1 XRP
            // increment reserve is for the buy offer, and 1 XRP is for offer
            // price
            env.fund(acctReserve + incReserve + XRP(1), bob);
            env.close();
 
            // Alice mints a NFT
            uint256 const nftId{token::getNextID(env, alice, 0u, tfTransferable)};
            env(token::mint(alice, 0u), txflags(tfTransferable));
            env.close();
 
            // Bob makes a buy offer for 1 XRP
            auto const buyOfferIndex = keylet::nftoffer(bob, env.seq(bob)).key;
            env(token::createOffer(bob, nftId, XRP(1)), token::owner(alice));
            env.close();
 
            // accepting the buy offer fails because bob's balance is `base fee`
            // drops lower than the required amount, since the previous tx burnt
            // drops for tx fee.
            env(token::acceptBuyOffer(alice, buyOfferIndex), ter(tecINSUFFICIENT_FUNDS));
            env.close();
 
            // send Bob `base fee` drops
            env(pay(env.master, bob, drops(baseFee)));
            env.close();
 
            // Now bob can buy the offer
            env(token::acceptBuyOffer(alice, buyOfferIndex));
            env.close();
        }
 
        // Test the reserve behavior in brokered mode.
        // The behavior should not change regardless whether fixNFTokenReserve
        // is enabled or not, since the ledger is able to guard against
        // free NFTokenPages in brokered mode. This is merely an
        // additional test to exercise existing offer behavior.
        {
            Account const alice{"alice"};
            Account const bob{"bob"};
            Account const broker{"broker"};
 
            Env env{*this, features};
            auto const acctReserve = env.current()->fees().reserve;
            auto const incReserve = env.current()->fees().increment;
            auto const baseFee = env.current()->fees().base;
 
            env.fund(XRP(10000), alice, broker);
            env.close();
 
            // Bob is funded with account reserve + incr reserve + 1 XRP(offer
            // price)
            env.fund(acctReserve + incReserve + XRP(1), bob);
            env.close();
 
            // Alice mints a NFT
            uint256 const nftId{token::getNextID(env, alice, 0u, tfTransferable)};
            env(token::mint(alice, 0u), txflags(tfTransferable));
            env.close();
 
            // Alice creates sell offer and set broker as destination
            uint256 const offerAliceToBroker = keylet::nftoffer(alice, env.seq(alice)).key;
            env(token::createOffer(alice, nftId, XRP(1)),
                token::destination(broker),
                txflags(tfSellNFToken));
            env.close();
 
            // Bob creates buy offer
            uint256 const offerBobToBroker = keylet::nftoffer(bob, env.seq(bob)).key;
            env(token::createOffer(bob, nftId, XRP(1)), token::owner(alice));
            env.close();
 
            // broker offers.
            // Returns insufficient funds, because bob burnt tx fee when he
            // created his buy offer, which makes his spendable balance to be
            // less than the required amount.
            env(token::brokerOffers(broker, offerBobToBroker, offerAliceToBroker),
                ter(tecINSUFFICIENT_FUNDS));
            env.close();
 
            // send Bob `base fee` drops
            env(pay(env.master, bob, drops(baseFee)));
            env.close();
 
            // broker offers.
            env(token::brokerOffers(broker, offerBobToBroker, offerAliceToBroker));
            env.close();
        }
    }
 
    void
    testUnaskedForAutoTrustline(FeatureBitset features)
    {
        testcase("Test fix unasked for auto-trustline.");
 
        using namespace test::jtx;
 
        Account const issuer{"issuer"};
        Account const becky{"becky"};
        Account const cheri{"cheri"};
        Account const gw("gw");
        IOU const gwAUD(gw["AUD"]);
 
        // This test case covers issue...
        // https://github.com/XRPLF/rippled/issues/4925
        //
        // For an NFToken with a transfer fee, the issuer must be able to
        // accept the transfer fee or else a transfer should fail.  If the
        // NFToken is transferred for a non-XRP asset, then the issuer must
        // have a trustline to that asset to receive the fee.
        //
        // This test looks at a situation where issuer would get a trustline
        // for the fee without the issuer's consent.  Here are the steps:
        //  1. Issuer has a trustline (i.e., USD)
        //  2. Issuer mints NFToken with transfer fee.
        //  3. Becky acquires the NFToken, paying with XRP.
        //  4. Becky creates offer to sell NFToken for USD(100).
        //  5. Issuer deletes trustline for USD.
        //  6. Carol buys NFToken from Becky for USD(100).
        //  7. The transfer fee from Carol's purchase re-establishes issuer's
        //     USD trustline.
        //
        // The fixEnforceNFTokenTrustline amendment addresses this oversight.
        //
        // We run this test case both with and without
        // fixEnforceNFTokenTrustline enabled so we can see the change
        // in behavior.
        //
        // In both cases we remove the fixRemoveNFTokenAutoTrustLine amendment.
        // Otherwise we can't create NFTokens with tfTrustLine enabled.
        FeatureBitset const localFeatures = features - fixRemoveNFTokenAutoTrustLine;
        for (FeatureBitset feats :
             {localFeatures - fixEnforceNFTokenTrustline,
              localFeatures | fixEnforceNFTokenTrustline})
        {
            Env env{*this, feats};
            env.fund(XRP(1000), issuer, becky, cheri, gw);
            env.close();
 
            // Set trust lines so becky and cheri can use gw's currency.
            env(trust(becky, gwAUD(1000)));
            env(trust(cheri, gwAUD(1000)));
            env.close();
            env(pay(gw, cheri, gwAUD(500)));
            env.close();
 
            // issuer creates two NFTs: one with and one without AutoTrustLine.
            std::uint16_t const xferFee = 5000;  // 5%
            uint256 const nftAutoTrustID{
                token::getNextID(env, issuer, 0u, tfTransferable | tfTrustLine, xferFee)};
            env(token::mint(issuer, 0u),
                token::xferFee(xferFee),
                txflags(tfTransferable | tfTrustLine));
            env.close();
 
            uint256 const nftNoAutoTrustID{
                token::getNextID(env, issuer, 0u, tfTransferable, xferFee)};
            env(token::mint(issuer, 0u), token::xferFee(xferFee), txflags(tfTransferable));
            env.close();
 
            // becky buys the nfts for 1 drop each.
            {
                uint256 const beckyBuyOfferIndex1 = keylet::nftoffer(becky, env.seq(becky)).key;
                env(token::createOffer(becky, nftAutoTrustID, drops(1)), token::owner(issuer));
 
                uint256 const beckyBuyOfferIndex2 = keylet::nftoffer(becky, env.seq(becky)).key;
                env(token::createOffer(becky, nftNoAutoTrustID, drops(1)), token::owner(issuer));
 
                env.close();
                env(token::acceptBuyOffer(issuer, beckyBuyOfferIndex1));
                env(token::acceptBuyOffer(issuer, beckyBuyOfferIndex2));
                env.close();
            }
 
            // becky creates offers to sell the nfts for AUD.
            uint256 const beckyAutoTrustOfferIndex = keylet::nftoffer(becky, env.seq(becky)).key;
            env(token::createOffer(becky, nftAutoTrustID, gwAUD(100)), txflags(tfSellNFToken));
            env.close();
 
            // Creating an offer for the NFToken without tfTrustLine fails
            // because issuer does not have a trust line for AUD.
            env(token::createOffer(becky, nftNoAutoTrustID, gwAUD(100)),
                txflags(tfSellNFToken),
                ter(tecNO_LINE));
            env.close();
 
            // issuer creates a trust line.  Now the offer create for the
            // NFToken without tfTrustLine succeeds.
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            env(trust(issuer, gwAUD(1000)));
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 1);
 
            uint256 const beckyNoAutoTrustOfferIndex = keylet::nftoffer(becky, env.seq(becky)).key;
            env(token::createOffer(becky, nftNoAutoTrustID, gwAUD(100)), txflags(tfSellNFToken));
            env.close();
 
            // Now that the offers are in place, issuer removes the trustline.
            BEAST_EXPECT(ownerCount(env, issuer) == 1);
            env(trust(issuer, gwAUD(0)));
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
 
            // cheri attempts to accept becky's offers.  Behavior with the
            // AutoTrustline NFT is uniform: issuer gets a new trust line.
            env(token::acceptSellOffer(cheri, beckyAutoTrustOfferIndex));
            env.close();
 
            // Here's evidence that issuer got the new AUD trust line.
            BEAST_EXPECT(ownerCount(env, issuer) == 1);
            BEAST_EXPECT(env.balance(issuer, gwAUD) == gwAUD(5));
 
            // issuer once again removes the trust line for AUD.
            env(pay(issuer, gw, gwAUD(5)));
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
 
            // cheri attempts to accept the NoAutoTrustLine NFT.  Behavior
            // depends on whether fixEnforceNFTokenTrustline is enabled.
            if (feats[fixEnforceNFTokenTrustline])
            {
                // With fixEnforceNFTokenTrustline cheri can't accept the
                // offer because issuer could not get their transfer fee
                // without the appropriate trustline.
                env(token::acceptSellOffer(cheri, beckyNoAutoTrustOfferIndex), ter(tecNO_LINE));
                env.close();
 
                // But if issuer re-establishes the trustline then the offer
                // can be accepted.
                env(trust(issuer, gwAUD(1000)));
                env.close();
                BEAST_EXPECT(ownerCount(env, issuer) == 1);
 
                env(token::acceptSellOffer(cheri, beckyNoAutoTrustOfferIndex));
                env.close();
            }
            else
            {
                // Without fixEnforceNFTokenTrustline the offer just works
                // and issuer gets a trustline that they did not request.
                env(token::acceptSellOffer(cheri, beckyNoAutoTrustOfferIndex));
                env.close();
            }
            BEAST_EXPECT(ownerCount(env, issuer) == 1);
            BEAST_EXPECT(env.balance(issuer, gwAUD) == gwAUD(5));
        }  // for feats
    }
 
    void
    testNFTIssuerIsIOUIssuer(FeatureBitset features)
    {
        testcase("Test fix NFT issuer is IOU issuer");
 
        using namespace test::jtx;
 
        Account const issuer{"issuer"};
        Account const becky{"becky"};
        Account const cheri{"cheri"};
        IOU const isISU(issuer["ISU"]);
 
        // This test case covers issue...
        // https://github.com/XRPLF/rippled/issues/4941
        //
        // If an NFToken has a transfer fee then, when an offer is accepted,
        // a portion of the sale price goes to the issuer.
        //
        // It is possible for an issuer to issue both an IOU (for remittances)
        // and NFTokens.  If the issuer's IOU is used to pay for the transfer
        // of one of the issuer's NFTokens, then paying the fee for that
        // transfer will fail with a tecNO_LINE.
        //
        // The problem occurs because the NFT code looks for a trust line to
        // pay the transfer fee.  However the issuer of an IOU does not need
        // a trust line to accept their own issuance and, in fact, is not
        // allowed to have a trust line to themselves.
        //
        // This test looks at a situation where transfer of an NFToken is
        // prevented by this bug:
        //  1. Issuer issues an IOU (e.g, isISU).
        //  2. Becky and Cheri get trust lines for, and acquire, some isISU.
        //  3. Issuer mints NFToken with transfer fee.
        //  4. Becky acquires the NFToken, paying with XRP.
        //  5. Becky attempts to create an offer to sell the NFToken for
        //     isISU(100).  The attempt fails with `tecNO_LINE`.
        //
        // The featureNFTokenMintOffer amendment addresses this oversight.
        //
        // We remove the fixRemoveNFTokenAutoTrustLine amendment.  Otherwise
        // we can't create NFTokens with tfTrustLine enabled.
        FeatureBitset const localFeatures = features - fixRemoveNFTokenAutoTrustLine;
 
        Env env{*this, localFeatures};
        env.fund(XRP(1000), issuer, becky, cheri);
        env.close();
 
        // Set trust lines so becky and cheri can use isISU.
        env(trust(becky, isISU(1000)));
        env(trust(cheri, isISU(1000)));
        env.close();
        env(pay(issuer, cheri, isISU(500)));
        env.close();
 
        // issuer creates two NFTs: one with and one without AutoTrustLine.
        std::uint16_t const xferFee = 5000;  // 5%
        uint256 const nftAutoTrustID{
            token::getNextID(env, issuer, 0u, tfTransferable | tfTrustLine, xferFee)};
        env(token::mint(issuer, 0u),
            token::xferFee(xferFee),
            txflags(tfTransferable | tfTrustLine));
        env.close();
 
        uint256 const nftNoAutoTrustID{token::getNextID(env, issuer, 0u, tfTransferable, xferFee)};
        env(token::mint(issuer, 0u), token::xferFee(xferFee), txflags(tfTransferable));
        env.close();
 
        // becky buys the nfts for 1 drop each.
        {
            uint256 const beckyBuyOfferIndex1 = keylet::nftoffer(becky, env.seq(becky)).key;
            env(token::createOffer(becky, nftAutoTrustID, drops(1)), token::owner(issuer));
 
            uint256 const beckyBuyOfferIndex2 = keylet::nftoffer(becky, env.seq(becky)).key;
            env(token::createOffer(becky, nftNoAutoTrustID, drops(1)), token::owner(issuer));
 
            env.close();
            env(token::acceptBuyOffer(issuer, beckyBuyOfferIndex1));
            env(token::acceptBuyOffer(issuer, beckyBuyOfferIndex2));
            env.close();
        }
 
        // Behavior from here down diverges significantly based on
        // featureNFTokenMintOffer.
        if (!localFeatures[featureNFTokenMintOffer])
        {
            // Without featureNFTokenMintOffer becky simply can't
            // create an offer for a non-tfTrustLine NFToken that would
            // pay the transfer fee in issuer's own IOU.
            env(token::createOffer(becky, nftNoAutoTrustID, isISU(100)),
                txflags(tfSellNFToken),
                ter(tecNO_LINE));
            env.close();
 
            // And issuer can't create a trust line to themselves.
            env(trust(issuer, isISU(1000)), ter(temDST_IS_SRC));
            env.close();
 
            // However if the NFToken has the tfTrustLine flag set,
            // then becky can create the offer.
            uint256 const beckyAutoTrustOfferIndex = keylet::nftoffer(becky, env.seq(becky)).key;
            env(token::createOffer(becky, nftAutoTrustID, isISU(100)), txflags(tfSellNFToken));
            env.close();
 
            // And cheri can accept the offer.
            env(token::acceptSellOffer(cheri, beckyAutoTrustOfferIndex));
            env.close();
 
            // We verify that issuer got their transfer fee by seeing that
            // ISU(5) has disappeared out of cheri's and becky's balances.
            BEAST_EXPECT(env.balance(becky, isISU) == isISU(95));
            BEAST_EXPECT(env.balance(cheri, isISU) == isISU(400));
        }
        else
        {
            // With featureNFTokenMintOffer things go better.
            // becky creates offers to sell the nfts for ISU.
            uint256 const beckyNoAutoTrustOfferIndex = keylet::nftoffer(becky, env.seq(becky)).key;
            env(token::createOffer(becky, nftNoAutoTrustID, isISU(100)), txflags(tfSellNFToken));
            env.close();
            uint256 const beckyAutoTrustOfferIndex = keylet::nftoffer(becky, env.seq(becky)).key;
            env(token::createOffer(becky, nftAutoTrustID, isISU(100)), txflags(tfSellNFToken));
            env.close();
 
            // cheri accepts becky's offers.  Behavior is uniform:
            // issuer gets paid.
            env(token::acceptSellOffer(cheri, beckyAutoTrustOfferIndex));
            env.close();
 
            // We verify that issuer got their transfer fee by seeing that
            // ISU(5) has disappeared out of cheri's and becky's balances.
            BEAST_EXPECT(env.balance(becky, isISU) == isISU(95));
            BEAST_EXPECT(env.balance(cheri, isISU) == isISU(400));
 
            env(token::acceptSellOffer(cheri, beckyNoAutoTrustOfferIndex));
            env.close();
 
            // We verify that issuer got their transfer fee by seeing that
            // an additional ISU(5) has disappeared out of cheri's and
            // becky's balances.
            BEAST_EXPECT(env.balance(becky, isISU) == isISU(190));
            BEAST_EXPECT(env.balance(cheri, isISU) == isISU(300));
        }
    }
 
    void
    testNFTokenModify(FeatureBitset features)
    {
        testcase("Test NFTokenModify");
 
        using namespace test::jtx;
 
        Account const issuer{"issuer"};
        Account const alice("alice");
        Account const bob("bob");
 
        bool const modifyEnabled = features[featureDynamicNFT];
 
        {
            // Mint with tfMutable
            Env env{*this, features};
            env.fund(XRP(10000), issuer);
            env.close();
 
            auto const expectedTer = modifyEnabled ? TER{tesSUCCESS} : TER{temINVALID_FLAG};
            env(token::mint(issuer, 0u), txflags(tfMutable), ter(expectedTer));
            env.close();
        }
        {
            Env env{*this, features};
            env.fund(XRP(10000), issuer);
            env.close();
 
            // Modify a nftoken
            uint256 const nftId{token::getNextID(env, issuer, 0u, tfMutable)};
            if (modifyEnabled)
            {
                env(token::mint(issuer, 0u), txflags(tfMutable));
                env.close();
                BEAST_EXPECT(ownerCount(env, issuer) == 1);
                env(token::modify(issuer, nftId));
                BEAST_EXPECT(ownerCount(env, issuer) == 1);
            }
            else
            {
                env(token::mint(issuer, 0u));
                env.close();
                env(token::modify(issuer, nftId), ter(temDISABLED));
                env.close();
            }
        }
        if (!modifyEnabled)
            return;
 
        {
            Env env{*this, features};
            env.fund(XRP(10000), issuer);
            env.close();
 
            uint256 const nftId{token::getNextID(env, issuer, 0u, tfMutable)};
            env(token::mint(issuer, 0u), txflags(tfMutable));
            env.close();
 
            // Set a negative fee. Exercises invalid preflight1.
            env(token::modify(issuer, nftId), fee(STAmount(10ull, true)), ter(temBAD_FEE));
            env.close();
 
            // Invalid Flags
            env(token::modify(issuer, nftId), txflags(0x00000001), ter(temINVALID_FLAG));
 
            // Invalid Owner
            env(token::modify(issuer, nftId), token::owner(issuer), ter(temMALFORMED));
            env.close();
 
            // Invalid URI length = 0
            env(token::modify(issuer, nftId), token::uri(""), ter(temMALFORMED));
            env.close();
 
            // Invalid URI length > 256
            env(token::modify(issuer, nftId),
                token::uri(std::string(maxTokenURILength + 1, 'q')),
                ter(temMALFORMED));
            env.close();
        }
        {
            Env env{*this, features};
            env.fund(XRP(10000), issuer, alice, bob);
            env.close();
 
            {
                // NFToken not exists
                uint256 const nftIDNotExists{token::getNextID(env, issuer, 0u, tfMutable)};
                env.close();
 
                env(token::modify(issuer, nftIDNotExists), ter(tecNO_ENTRY));
                env.close();
            }
            {
                // Invalid NFToken flag
                uint256 const nftIDNotModifiable{token::getNextID(env, issuer, 0u)};
                env(token::mint(issuer, 0u));
                env.close();
 
                env(token::modify(issuer, nftIDNotModifiable), ter(tecNO_PERMISSION));
                env.close();
            }
            {
                // Unauthorized account
                uint256 const nftId{token::getNextID(env, issuer, 0u, tfMutable)};
                env(token::mint(issuer, 0u), txflags(tfMutable));
                env.close();
 
                env(token::modify(bob, nftId), token::owner(issuer), ter(tecNO_PERMISSION));
                env.close();
 
                env(token::setMinter(issuer, alice));
                env.close();
 
                env(token::modify(bob, nftId), token::owner(issuer), ter(tecNO_PERMISSION));
                env.close();
            }
        }
        {
            Env env{*this, features};
            env.fund(XRP(10000), issuer, alice, bob);
            env.close();
 
            // modify with tfFullyCanonicalSig should success
            uint256 const nftId{token::getNextID(env, issuer, 0u, tfMutable)};
            env(token::mint(issuer, 0u), txflags(tfMutable), token::uri("uri"));
            env.close();
 
            env(token::modify(issuer, nftId), txflags(tfFullyCanonicalSig));
            env.close();
        }
        {
            Env env{*this, features};
            env.fund(XRP(10000), issuer, alice, bob);
            env.close();
 
            // lambda that returns the JSON form of NFTokens held by acct
            auto accountNFTs = [&env](Account const& acct) {
                Json::Value params;
                params[jss::account] = acct.human();
                params[jss::type] = "state";
                auto response = env.rpc("json", "account_nfts", to_string(params));
                return response[jss::result][jss::account_nfts];
            };
 
            // lambda that checks for the expected URI value of an NFToken
            auto checkURI = [&accountNFTs, this](Account const& acct, char const* uri, int line) {
                auto const nfts = accountNFTs(acct);
                if (nfts.size() == 1)
                {
                    pass();
                }
                else
                {
                    std::ostringstream text;
                    text << "checkURI: unexpected NFT count on line " << line;
                    fail(text.str(), __FILE__, line);
                    return;
                }
 
                if (uri == nullptr)
                {
                    if (!nfts[0u].isMember(sfURI.jsonName))
                    {
                        pass();
                    }
                    else
                    {
                        std::ostringstream text;
                        text << "checkURI: unexpected URI present on line " << line;
                        fail(text.str(), __FILE__, line);
                    }
                    return;
                }
 
                if (nfts[0u][sfURI.jsonName] == strHex(std::string(uri)))
                {
                    pass();
                }
                else
                {
                    std::ostringstream text;
                    text << "checkURI: unexpected URI contents on line " << line;
                    fail(text.str(), __FILE__, line);
                }
            };
 
            uint256 const nftId{token::getNextID(env, issuer, 0u, tfMutable)};
            env.close();
 
            env(token::mint(issuer, 0u), txflags(tfMutable), token::uri("uri"));
            env.close();
            checkURI(issuer, "uri", __LINE__);
 
            // set URI Field
            env(token::modify(issuer, nftId), token::uri("new_uri"));
            env.close();
            checkURI(issuer, "new_uri", __LINE__);
 
            // unset URI Field
            env(token::modify(issuer, nftId));
            env.close();
            checkURI(issuer, nullptr, __LINE__);
 
            // set URI Field
            env(token::modify(issuer, nftId), token::uri("uri"));
            env.close();
            checkURI(issuer, "uri", __LINE__);
 
            // Account != Owner
            uint256 const offerID = keylet::nftoffer(issuer, env.seq(issuer)).key;
            env(token::createOffer(issuer, nftId, XRP(0)), txflags(tfSellNFToken));
            env.close();
            env(token::acceptSellOffer(alice, offerID));
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            BEAST_EXPECT(ownerCount(env, alice) == 1);
            checkURI(alice, "uri", __LINE__);
 
            // Modify by owner fails.
            env(token::modify(alice, nftId), token::uri("new_uri"), ter(tecNO_PERMISSION));
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            BEAST_EXPECT(ownerCount(env, alice) == 1);
            checkURI(alice, "uri", __LINE__);
 
            env(token::modify(issuer, nftId), token::owner(alice), token::uri("new_uri"));
            env.close();
            BEAST_EXPECT(ownerCount(env, issuer) == 0);
            BEAST_EXPECT(ownerCount(env, alice) == 1);
            checkURI(alice, "new_uri", __LINE__);
 
            env(token::modify(issuer, nftId), token::owner(alice));
            env.close();
            checkURI(alice, nullptr, __LINE__);
 
            env(token::modify(issuer, nftId), token::owner(alice), token::uri("uri"));
            env.close();
            checkURI(alice, "uri", __LINE__);
 
            // Modify by authorized minter
            env(token::setMinter(issuer, bob));
            env.close();
            env(token::modify(bob, nftId), token::owner(alice), token::uri("new_uri"));
            env.close();
            checkURI(alice, "new_uri", __LINE__);
 
            env(token::modify(bob, nftId), token::owner(alice));
            env.close();
            checkURI(alice, nullptr, __LINE__);
 
            env(token::modify(bob, nftId), token::owner(alice), token::uri("uri"));
            env.close();
            checkURI(alice, "uri", __LINE__);
        }
    }
 
protected:
    FeatureBitset const allFeatures{test::jtx::testable_amendments()};
 
    void
    testWithFeats(FeatureBitset features)
    {
        testEnabled(features);
        testMintReserve(features);
        testMintMaxTokens(features);
        testMintInvalid(features);
        testBurnInvalid(features);
        testCreateOfferInvalid(features);
        testCancelOfferInvalid(features);
        testAcceptOfferInvalid(features);
        testMintFlagBurnable(features);
        testMintFlagOnlyXRP(features);
        testMintFlagCreateTrustLine(features);
        testMintFlagTransferable(features);
        testMintTransferFee(features);
        testMintTaxon(features);
        testMintURI(features);
        testCreateOfferDestination(features);
        testCreateOfferDestinationDisallowIncoming(features);
        testCreateOfferExpiration(features);
        testCancelOffers(features);
        testCancelTooManyOffers(features);
        testBrokeredAccept(features);
        testNFTokenOfferOwner(features);
        testNFTokenWithTickets(features);
        testNFTokenDeleteAccount(features);
        testNftXxxOffers(features);
        testNFTokenNegOffer(features);
        testIOUWithTransferFee(features);
        testBrokeredSaleToSelf(features);
        testNFTokenRemint(features);
        testFeatMintWithOffer(features);
        testTxJsonMetaFields(features);
        testFixNFTokenBuyerReserve(features);
        testUnaskedForAutoTrustline(features);
        testNFTIssuerIsIOUIssuer(features);
        testNFTokenModify(features);
    }
 
public:
    void
    run() override
    {
        testWithFeats(
            allFeatures - fixNFTokenReserve - featureNFTokenMintOffer - featureDynamicNFT -
            fixExpiredNFTokenOfferRemoval);
    }
};
 
class NFTokenDisallowIncoming_test : public NFTokenBaseUtil_test
{
    void
    run() override
    {
        testWithFeats(
            allFeatures - fixNFTokenReserve - featureNFTokenMintOffer - featureDynamicNFT);
    }
};
 
class NFTokenWOMintOffer_test : public NFTokenBaseUtil_test
{
    void
    run() override
    {
        testWithFeats(allFeatures - featureNFTokenMintOffer - featureDynamicNFT);
    }
};
 
class NFTokenWOModify_test : public NFTokenBaseUtil_test
{
    void
    run() override
    {
        testWithFeats(allFeatures - featureDynamicNFT);
    }
};
 
class NFTokenWOExpiredOfferRemoval_test : public NFTokenBaseUtil_test
{
    void
    run() override
    {
        testWithFeats(allFeatures - fixExpiredNFTokenOfferRemoval);
    }
};
 
class NFTokenAllFeatures_test : public NFTokenBaseUtil_test
{
    void
    run() override
    {
        testWithFeats(allFeatures);
    }
};
 
BEAST_DEFINE_TESTSUITE_PRIO(NFTokenBaseUtil, app, xrpl, 2);
BEAST_DEFINE_TESTSUITE_PRIO(NFTokenDisallowIncoming, app, xrpl, 2);
BEAST_DEFINE_TESTSUITE_PRIO(NFTokenWOMintOffer, app, xrpl, 2);
BEAST_DEFINE_TESTSUITE_PRIO(NFTokenWOModify, app, xrpl, 2);
BEAST_DEFINE_TESTSUITE_PRIO(NFTokenAllFeatures, app, xrpl, 2);
 
}  // namespace xrpl