Consensus_test.cpp

#include <test/csf.h>
#include <test/unit_test/SuiteJournal.h>
 
#include <xrpld/consensus/Consensus.h>
 
#include <xrpl/beast/unit_test.h>
#include <xrpl/json/to_string.h>
 
namespace xrpl {
namespace test {
 
class Consensus_test : public beast::unit_test::suite
{
    SuiteJournal journal_;
 
public:
    Consensus_test() : journal_("Consensus_test", *this)
    {
    }
 
    void
    testShouldCloseLedger()
    {
        using namespace std::chrono_literals;
        testcase("should close ledger");
 
        // Use default parameters
        ConsensusParms const p{};
 
        // Bizarre times forcibly close
        BEAST_EXPECT(shouldCloseLedger(true, 10, 10, 10, -10s, 10s, 1s, 1s, p, journal_));
        BEAST_EXPECT(shouldCloseLedger(true, 10, 10, 10, 100h, 10s, 1s, 1s, p, journal_));
        BEAST_EXPECT(shouldCloseLedger(true, 10, 10, 10, 10s, 100h, 1s, 1s, p, journal_));
 
        // Rest of network has closed
        BEAST_EXPECT(shouldCloseLedger(true, 10, 3, 5, 10s, 10s, 10s, 10s, p, journal_));
 
        // No transactions means wait until end of internval
        BEAST_EXPECT(!shouldCloseLedger(false, 10, 0, 0, 1s, 1s, 1s, 10s, p, journal_));
        BEAST_EXPECT(shouldCloseLedger(false, 10, 0, 0, 1s, 10s, 1s, 10s, p, journal_));
 
        // Enforce minimum ledger open time
        BEAST_EXPECT(!shouldCloseLedger(true, 10, 0, 0, 10s, 10s, 1s, 10s, p, journal_));
 
        // Don't go too much faster than last time
        BEAST_EXPECT(!shouldCloseLedger(true, 10, 0, 0, 10s, 10s, 3s, 10s, p, journal_));
 
        BEAST_EXPECT(shouldCloseLedger(true, 10, 0, 0, 10s, 10s, 10s, 10s, p, journal_));
    }
 
    void
    testCheckConsensus()
    {
        using namespace std::chrono_literals;
        testcase("check consensus");
 
        // Use default parameters
        ConsensusParms const p{};
 
        // Disputes still in doubt
        //
        // Not enough time has elapsed
        BEAST_EXPECT(
            ConsensusState::No == checkConsensus(10, 2, 2, 0, 3s, 2s, false, p, true, journal_));
 
        // If not enough peers have proposed, ensure
        // more time for proposals
        BEAST_EXPECT(
            ConsensusState::No == checkConsensus(10, 2, 2, 0, 3s, 4s, false, p, true, journal_));
 
        // Enough time has elapsed and we all agree
        BEAST_EXPECT(
            ConsensusState::Yes == checkConsensus(10, 2, 2, 0, 3s, 10s, false, p, true, journal_));
 
        // Enough time has elapsed and we don't yet agree
        BEAST_EXPECT(
            ConsensusState::No == checkConsensus(10, 2, 1, 0, 3s, 10s, false, p, true, journal_));
 
        // Our peers have moved on
        // Enough time has elapsed and we all agree
        BEAST_EXPECT(
            ConsensusState::MovedOn ==
            checkConsensus(10, 2, 1, 8, 3s, 10s, false, p, true, journal_));
 
        // If no peers, don't agree until time has passed.
        BEAST_EXPECT(
            ConsensusState::No == checkConsensus(0, 0, 0, 0, 3s, 10s, false, p, true, journal_));
 
        // Agree if no peers and enough time has passed.
        BEAST_EXPECT(
            ConsensusState::Yes == checkConsensus(0, 0, 0, 0, 3s, 16s, false, p, true, journal_));
 
        // Expire if too much time has passed without agreement
        BEAST_EXPECT(
            ConsensusState::Expired ==
            checkConsensus(10, 8, 1, 0, 1s, 19s, false, p, true, journal_));
 
        // Stalled
        //
        // Not enough time has elapsed
        BEAST_EXPECT(
            ConsensusState::No == checkConsensus(10, 2, 2, 0, 3s, 2s, true, p, true, journal_));
 
        // If not enough peers have proposed, ensure
        // more time for proposals
        BEAST_EXPECT(
            ConsensusState::No == checkConsensus(10, 2, 2, 0, 3s, 4s, true, p, true, journal_));
 
        // Enough time has elapsed and we all agree
        BEAST_EXPECT(
            ConsensusState::Yes == checkConsensus(10, 2, 2, 0, 3s, 10s, true, p, true, journal_));
 
        // Enough time has elapsed and we don't yet agree, but there's nothing
        // left to dispute
        BEAST_EXPECT(
            ConsensusState::Yes == checkConsensus(10, 2, 1, 0, 3s, 10s, true, p, true, journal_));
 
        // Our peers have moved on
        // Enough time has elapsed and we all agree, nothing left to dispute
        BEAST_EXPECT(
            ConsensusState::Yes == checkConsensus(10, 2, 1, 8, 3s, 10s, true, p, true, journal_));
 
        // If no peers, don't agree until time has passed.
        BEAST_EXPECT(
            ConsensusState::No == checkConsensus(0, 0, 0, 0, 3s, 10s, true, p, true, journal_));
 
        // Agree if no peers and enough time has passed.
        BEAST_EXPECT(
            ConsensusState::Yes == checkConsensus(0, 0, 0, 0, 3s, 16s, true, p, true, journal_));
 
        // We are done if there's nothing left to dispute, no matter how much
        // time has passed
        BEAST_EXPECT(
            ConsensusState::Yes == checkConsensus(10, 8, 1, 0, 1s, 19s, true, p, true, journal_));
    }
 
    void
    testStandalone()
    {
        using namespace std::chrono_literals;
        using namespace csf;
        testcase("standalone");
 
        Sim s;
        PeerGroup const peers = s.createGroup(1);
        Peer* peer = peers[0];
        peer->targetLedgers = 1;
        peer->start();
        peer->submit(Tx{1});
 
        s.scheduler.step();
 
        // Inspect that the proper ledger was created
        auto const& lcl = peer->lastClosedLedger;
        BEAST_EXPECT(peer->prevLedgerID() == lcl.id());
        BEAST_EXPECT(lcl.seq() == Ledger::Seq{1});
        BEAST_EXPECT(lcl.txs().size() == 1);
        BEAST_EXPECT(lcl.txs().contains(Tx{1}));
        BEAST_EXPECT(peer->prevProposers == 0);
    }
 
    void
    testPeersAgree()
    {
        using namespace csf;
        using namespace std::chrono;
        testcase("peers agree");
 
        ConsensusParms const parms{};
        Sim sim;
        PeerGroup peers = sim.createGroup(5);
 
        // Connected trust and network graphs with single fixed delay
        peers.trustAndConnect(peers, round<milliseconds>(0.2 * parms.ledgerGRANULARITY));
 
        // everyone submits their own ID as a TX
        for (Peer* p : peers)
            p->submit(Tx(static_cast<std::uint32_t>(p->id)));
 
        sim.run(1);
 
        // All peers are in sync
        if (BEAST_EXPECT(sim.synchronized()))
        {
            for (Peer const* peer : peers)
            {
                auto const& lcl = peer->lastClosedLedger;
                BEAST_EXPECT(lcl.id() == peer->prevLedgerID());
                BEAST_EXPECT(lcl.seq() == Ledger::Seq{1});
                // All peers proposed
                BEAST_EXPECT(peer->prevProposers == peers.size() - 1);
                // All transactions were accepted
                for (std::uint32_t i = 0; i < peers.size(); ++i)
                    BEAST_EXPECT(lcl.txs().contains(Tx{i}));
            }
        }
    }
 
    void
    testSlowPeers()
    {
        using namespace csf;
        using namespace std::chrono;
        testcase("slow peers");
 
        // Several tests of a complete trust graph with a subset of peers
        // that have significantly longer network delays to the rest of the
        // network
 
        // Test when a slow peer doesn't delay a consensus quorum (4/5 agree)
        {
            ConsensusParms const parms{};
            Sim sim;
            PeerGroup slow = sim.createGroup(1);
            PeerGroup fast = sim.createGroup(4);
            PeerGroup network = fast + slow;
 
            // Fully connected trust graph
            network.trust(network);
 
            // Fast and slow network connections
            fast.connect(fast, round<milliseconds>(0.2 * parms.ledgerGRANULARITY));
 
            slow.connect(network, round<milliseconds>(1.1 * parms.ledgerGRANULARITY));
 
            // All peers submit their own ID as a transaction
            for (Peer* peer : network)
                peer->submit(Tx{static_cast<std::uint32_t>(peer->id)});
 
            sim.run(1);
 
            // Verify all peers have same LCL but are missing transaction 0
            // All peers are in sync even with a slower peer 0
            if (BEAST_EXPECT(sim.synchronized()))
            {
                for (Peer const* peer : network)
                {
                    auto const& lcl = peer->lastClosedLedger;
                    BEAST_EXPECT(lcl.id() == peer->prevLedgerID());
                    BEAST_EXPECT(lcl.seq() == Ledger::Seq{1});
 
                    BEAST_EXPECT(peer->prevProposers == network.size() - 1);
                    BEAST_EXPECT(peer->prevRoundTime == network[0]->prevRoundTime);
 
                    BEAST_EXPECT(not lcl.txs().contains(Tx{0}));
                    for (std::uint32_t i = 2; i < network.size(); ++i)
                        BEAST_EXPECT(lcl.txs().contains(Tx{i}));
 
                    // Tx 0 didn't make it
                    BEAST_EXPECT(peer->openTxs.contains(Tx{0}));
                }
            }
        }
 
        // Test when the slow peers delay a consensus quorum (4/6 agree)
        {
            // Run two tests
            //  1. The slow peers are participating in consensus
            //  2. The slow peers are just observing
 
            for (auto isParticipant : {true, false})
            {
                ConsensusParms const parms{};
 
                Sim sim;
                PeerGroup slow = sim.createGroup(2);
                PeerGroup fast = sim.createGroup(4);
                PeerGroup network = fast + slow;
 
                // Connected trust graph
                network.trust(network);
 
                // Fast and slow network connections
                fast.connect(fast, round<milliseconds>(0.2 * parms.ledgerGRANULARITY));
 
                slow.connect(network, round<milliseconds>(1.1 * parms.ledgerGRANULARITY));
 
                for (Peer* peer : slow)
                    peer->runAsValidator = isParticipant;
 
                // All peers submit their own ID as a transaction and relay it
                // to peers
                for (Peer* peer : network)
                    peer->submit(Tx{static_cast<std::uint32_t>(peer->id)});
 
                sim.run(1);
 
                if (BEAST_EXPECT(sim.synchronized()))
                {
                    // Verify all peers have same LCL but are missing
                    // transaction 0,1 which was not received by all peers
                    // before the ledger closed
                    for (Peer const* peer : network)
                    {
                        // Closed ledger has all but transaction 0,1
                        auto const& lcl = peer->lastClosedLedger;
                        BEAST_EXPECT(lcl.seq() == Ledger::Seq{1});
                        BEAST_EXPECT(not lcl.txs().contains(Tx{0}));
                        BEAST_EXPECT(not lcl.txs().contains(Tx{1}));
                        for (std::uint32_t i = slow.size(); i < network.size(); ++i)
                            BEAST_EXPECT(lcl.txs().contains(Tx{i}));
 
                        // Tx 0-1 didn't make it
                        BEAST_EXPECT(peer->openTxs.contains(Tx{0}));
                        BEAST_EXPECT(peer->openTxs.contains(Tx{1}));
                    }
 
                    Peer const* slowPeer = slow[0];
                    if (isParticipant)
                    {
                        BEAST_EXPECT(slowPeer->prevProposers == network.size() - 1);
                    }
                    else
                    {
                        BEAST_EXPECT(slowPeer->prevProposers == fast.size());
                    }
 
                    for (Peer const* peer : fast)
                    {
                        // Due to the network link delay settings
                        //    Peer 0 initially proposes {0}
                        //    Peer 1 initially proposes {1}
                        //    Peers 2-5 initially propose {2,3,4,5}
                        // Since peers 2-5 agree, 4/6 > the initial 50% needed
                        // to include a disputed transaction, so Peer 0/1 switch
                        // to agree with those peers. Peer 0/1 then closes with
                        // an 80% quorum of agreeing positions (5/6) match.
                        //
                        // Peers 2-5 do not change position, since tx 0 or tx 1
                        // have less than the 50% initial threshold. They also
                        // cannot declare consensus, since 4/6 agreeing
                        // positions are < 80% threshold. They therefore need an
                        // additional timerEntry call to see the updated
                        // positions from Peer 0 & 1.
 
                        if (isParticipant)
                        {
                            BEAST_EXPECT(peer->prevProposers == network.size() - 1);
                            BEAST_EXPECT(peer->prevRoundTime > slowPeer->prevRoundTime);
                        }
                        else
                        {
                            BEAST_EXPECT(peer->prevProposers == fast.size() - 1);
                            // so all peers should have closed together
                            BEAST_EXPECT(peer->prevRoundTime == slowPeer->prevRoundTime);
                        }
                    }
                }
            }
        }
    }
 
    void
    testCloseTimeDisagree()
    {
        using namespace csf;
        using namespace std::chrono;
        testcase("close time disagree");
 
        // This is a very specialized test to get ledgers to disagree on
        // the close time. It unfortunately assumes knowledge about current
        // timing constants. This is a necessary evil to get coverage up
        // pending more extensive refactorings of timing constants.
 
        // In order to agree-to-disagree on the close time, there must be no
        // clear majority of nodes agreeing on a close time. This test
        // sets a relative offset to the peers internal clocks so that they
        // send proposals with differing times.
 
        // However, agreement is on the effective close time, not the
        // exact close time. The minimum closeTimeResolution is given by
        // ledgerPossibleTimeResolutions[0], which is currently 10s. This means
        // the skews need to be at least 10 seconds to have different effective
        // close times.
 
        // Complicating this matter is that nodes will ignore proposals
        // with times more than proposeFRESHNESS =20s in the past. So at
        // the minimum granularity, we have at most 3 types of skews
        // (0s,10s,20s).
 
        // This test therefore has 6 nodes, with 2 nodes having each type of
        // skew. Then no majority (1/3 < 1/2) of nodes will agree on an
        // actual close time.
 
        ConsensusParms const parms{};
        Sim sim;
 
        PeerGroup groupA = sim.createGroup(2);
        PeerGroup const groupB = sim.createGroup(2);
        PeerGroup const groupC = sim.createGroup(2);
        PeerGroup network = groupA + groupB + groupC;
 
        network.trust(network);
        network.connect(network, round<milliseconds>(0.2 * parms.ledgerGRANULARITY));
 
        // Run consensus without skew until we have a short close time
        // resolution
        Peer const* firstPeer = *groupA.begin();
        while (firstPeer->lastClosedLedger.closeTimeResolution() >= parms.proposeFRESHNESS)
            sim.run(1);
 
        // Introduce a shift on the time of 2/3 of peers
        for (Peer* peer : groupA)
            peer->clockSkew = parms.proposeFRESHNESS / 2;
        for (Peer* peer : groupB)
            peer->clockSkew = parms.proposeFRESHNESS;
 
        sim.run(1);
 
        // All nodes agreed to disagree on the close time
        if (BEAST_EXPECT(sim.synchronized()))
        {
            for (Peer const* peer : network)
                BEAST_EXPECT(!peer->lastClosedLedger.closeAgree());
        }
    }
 
    void
    testWrongLCL()
    {
        using namespace csf;
        using namespace std::chrono;
        testcase("wrong LCL");
 
        // Specialized test to exercise a temporary fork in which some peers
        // are working on an incorrect prior ledger.
 
        ConsensusParms const parms{};
 
        // Vary the time it takes to process validations to exercise detecting
        // the wrong LCL at different phases of consensus
        for (auto validationDelay : {0ms, parms.ledgerMIN_CLOSE})
        {
            // Consider 10 peers:
            // 0 1         2 3 4       5 6 7 8 9
            // minority   majorityA   majorityB
            //
            // Nodes 0-1 trust nodes 0-4
            // Nodes 2-9 trust nodes 2-9
            //
            // By submitting tx 0 to nodes 0-4 and tx 1 to nodes 5-9,
            // nodes 0-1 will generate the wrong LCL (with tx 0). The remaining
            // nodes will instead accept the ledger with tx 1.
 
            // Nodes 0-1 will detect this mismatch during a subsequent round
            // since nodes 2-4 will validate a different ledger.
 
            // Nodes 0-1 will acquire the proper ledger from the network and
            // resume consensus and eventually generate the dominant network
            // ledger.
 
            // This topology can potentially fork with the above trust relations
            // but that is intended for this test.
 
            Sim sim;
 
            PeerGroup minority = sim.createGroup(2);
            PeerGroup const majorityA = sim.createGroup(3);
            PeerGroup const majorityB = sim.createGroup(5);
 
            PeerGroup majority = majorityA + majorityB;
            PeerGroup const network = minority + majority;
 
            SimDuration const delay = round<milliseconds>(0.2 * parms.ledgerGRANULARITY);
            minority.trustAndConnect(minority + majorityA, delay);
            majority.trustAndConnect(majority, delay);
 
            CollectByNode<JumpCollector> jumps;
            sim.collectors.add(jumps);
 
            BEAST_EXPECT(sim.trustGraph.canFork(parms.minCONSENSUS_PCT / 100.));
 
            // initial round to set prior state
            sim.run(1);
 
            // Nodes in smaller UNL have seen tx 0, nodes in other unl have seen
            // tx 1
            for (Peer* peer : network)
                peer->delays.recvValidation = validationDelay;
            for (Peer* peer : (minority + majorityA))
                peer->openTxs.insert(Tx{0});
            for (Peer* peer : majorityB)
                peer->openTxs.insert(Tx{1});
 
            // Run for additional rounds
            // With no validation delay, only 2 more rounds are needed.
            //  1. Round to generate different ledgers
            //  2. Round to detect different prior ledgers (but still generate
            //    wrong ones) and recover within that round since wrong LCL
            //    is detected before we close
            //
            // With a validation delay of ledgerMIN_CLOSE, we need 3 more
            // rounds.
            //  1. Round to generate different ledgers
            //  2. Round to detect different prior ledgers (but still generate
            //     wrong ones) but end up declaring consensus on wrong LCL (but
            //     with the right transaction set!). This is because we detect
            //     the wrong LCL after we have closed the ledger, so we declare
            //     consensus based solely on our peer proposals. But we haven't
            //     had time to acquire the right ledger.
            //  3. Round to correct
            sim.run(3);
 
            // The network never actually forks, since node 0-1 never see a
            // quorum of validations to fully validate the incorrect chain.
 
            // However, for a non zero-validation delay, the network is not
            // synchronized because nodes 0 and 1 are running one ledger behind
            if (BEAST_EXPECT(sim.branches() == 1))
            {
                for (Peer const* peer : majority)
                {
                    // No jumps for majority nodes
                    BEAST_EXPECT(jumps[peer->id].closeJumps.empty());
                    BEAST_EXPECT(jumps[peer->id].fullyValidatedJumps.empty());
                }
                for (Peer const* peer : minority)
                {
                    auto& peerJumps = jumps[peer->id];
                    // last closed ledger jump between chains
                    {
                        if (BEAST_EXPECT(peerJumps.closeJumps.size() == 1))
                        {
                            JumpCollector::Jump const& jump = peerJumps.closeJumps.front();
                            // Jump is to a different chain
                            BEAST_EXPECT(jump.from.seq() <= jump.to.seq());
                            BEAST_EXPECT(!jump.to.isAncestor(jump.from));
                        }
                    }
                    // fully validated jump forward in same chain
                    {
                        if (BEAST_EXPECT(peerJumps.fullyValidatedJumps.size() == 1))
                        {
                            JumpCollector::Jump const& jump = peerJumps.fullyValidatedJumps.front();
                            // Jump is to a different chain with same seq
                            BEAST_EXPECT(jump.from.seq() < jump.to.seq());
                            BEAST_EXPECT(jump.to.isAncestor(jump.from));
                        }
                    }
                }
            }
        }
 
        {
            // Additional test engineered to switch LCL during the establish
            // phase. This was added to trigger a scenario that previously
            // crashed, in which switchLCL switched from establish to open
            // phase, but still processed the establish phase logic.
 
            // Loner node will accept an initial ledger A, but all other nodes
            // accept ledger B a bit later. By delaying the time it takes
            // to process a validation, loner node will detect the wrongLCL
            // after it is already in the establish phase of the next round.
 
            Sim sim;
            PeerGroup loner = sim.createGroup(1);
            PeerGroup const friends = sim.createGroup(3);
            loner.trust(loner + friends);
 
            PeerGroup const others = sim.createGroup(6);
            PeerGroup clique = friends + others;
            clique.trust(clique);
 
            PeerGroup network = loner + clique;
            network.connect(network, round<milliseconds>(0.2 * parms.ledgerGRANULARITY));
 
            // initial round to set prior state
            sim.run(1);
            for (Peer* peer : (loner + friends))
                peer->openTxs.insert(Tx(0));
            for (Peer* peer : others)
                peer->openTxs.insert(Tx(1));
 
            // Delay validation processing
            for (Peer* peer : network)
                peer->delays.recvValidation = parms.ledgerGRANULARITY;
 
            // additional rounds to generate wrongLCL and recover
            sim.run(2);
 
            // Check all peers recovered
            for (Peer const* p : network)
                BEAST_EXPECT(p->prevLedgerID() == network[0]->prevLedgerID());
        }
    }
 
    void
    testConsensusCloseTimeRounding()
    {
        using namespace csf;
        using namespace std::chrono;
        testcase("consensus close time rounding");
 
        // This is a specialized test engineered to yield ledgers with different
        // close times even though the peers believe they had close time
        // consensus on the ledger.
        ConsensusParms const parms;
 
        Sim sim;
 
        // This requires a group of 4 fast and 2 slow peers to create a
        // situation in which a subset of peers requires seeing additional
        // proposals to declare consensus.
        PeerGroup slow = sim.createGroup(2);
        PeerGroup fast = sim.createGroup(4);
        PeerGroup network = fast + slow;
 
        // Connected trust graph
        network.trust(network);
 
        // Fast and slow network connections
        fast.connect(fast, round<milliseconds>(0.2 * parms.ledgerGRANULARITY));
        slow.connect(network, round<milliseconds>(1.1 * parms.ledgerGRANULARITY));
 
        // Run to the ledger *prior* to decreasing the resolution
        sim.run(increaseLedgerTimeResolutionEvery - 2);
 
        // In order to create the discrepancy, we want a case where if
        //   X = effCloseTime(closeTime, resolution, parentCloseTime)
        //   X != effCloseTime(X, resolution, parentCloseTime)
        //
        // That is, the effective close time is not a fixed point. This can
        // happen if X = parentCloseTime + 1, but a subsequent rounding goes
        // to the next highest multiple of resolution.
 
        // So we want to find an offset  (now + offset) % 30s = 15
        //                               (now + offset) % 20s = 15
        // This way, the next ledger will close and round up   Due to the
        // network delay settings, the round of consensus will take 5s, so
        // the next ledger's close time will
 
        NetClock::duration when = network[0]->now().time_since_epoch();
 
        // Check we are before the 30s to 20s transition
        NetClock::duration const resolution = network[0]->lastClosedLedger.closeTimeResolution();
        BEAST_EXPECT(resolution == NetClock::duration{30s});
 
        while (((when % NetClock::duration{30s}) != NetClock::duration{15s}) ||
               ((when % NetClock::duration{20s}) != NetClock::duration{15s}))
            when += 1s;
        // Advance the clock without consensus running (IS THIS WHAT
        // PREVENTS IT IN PRACTICE?)
        sim.scheduler.step_for(NetClock::time_point{when} - network[0]->now());
 
        // Run one more ledger with 30s resolution
        sim.run(1);
        if (BEAST_EXPECT(sim.synchronized()))
        {
            // close time should be ahead of clock time since we engineered
            // the close time to round up
            for (Peer const* peer : network)
            {
                BEAST_EXPECT(peer->lastClosedLedger.closeTime() > peer->now());
                BEAST_EXPECT(peer->lastClosedLedger.closeAgree());
            }
        }
 
        // All peers submit their own ID as a transaction
        for (Peer* peer : network)
            peer->submit(Tx{static_cast<std::uint32_t>(peer->id)});
 
        // Run 1 more round, this time it will have a decreased
        // resolution of 20 seconds.
 
        // The network delays are engineered so that the slow peers
        // initially have the wrong tx hash, but they see a majority
        // of agreement from their peers and declare consensus
        //
        // The trick is that everyone starts with a raw close time of
        //  84681s
        // Which has
        //   effCloseTime(86481s, 20s,  86490s) = 86491s
        // However, when the slow peers update their position, they change
        // the close time to 86451s. The fast peers declare consensus with
        // the 86481s as their position still.
        //
        // When accepted the ledger
        // - fast peers use eff(86481s) -> 86491s as the close time
        // - slow peers use eff(eff(86481s)) -> eff(86491s) -> 86500s!
 
        sim.run(1);
 
        BEAST_EXPECT(sim.synchronized());
    }
 
    void
    testFork()
    {
        using namespace csf;
        using namespace std::chrono;
        testcase("fork");
 
        std::uint32_t const numPeers = 10;
        // Vary overlap between two UNLs
        for (std::uint32_t overlap = 0; overlap <= numPeers; ++overlap)
        {
            ConsensusParms const parms{};
            Sim sim;
 
            std::uint32_t const numA = (numPeers - overlap) / 2;
            std::uint32_t const numB = numPeers - numA - overlap;
 
            PeerGroup const aOnly = sim.createGroup(numA);
            PeerGroup const bOnly = sim.createGroup(numB);
            PeerGroup const commonOnly = sim.createGroup(overlap);
 
            PeerGroup a = aOnly + commonOnly;
            PeerGroup b = bOnly + commonOnly;
 
            PeerGroup const network = a + b;
 
            SimDuration const delay = round<milliseconds>(0.2 * parms.ledgerGRANULARITY);
            a.trustAndConnect(a, delay);
            b.trustAndConnect(b, delay);
 
            // Initial round to set prior state
            sim.run(1);
            for (Peer* peer : network)
            {
                // Nodes have only seen transactions from their neighbors
                peer->openTxs.insert(Tx{static_cast<std::uint32_t>(peer->id)});
                for (Peer const* to : sim.trustGraph.trustedPeers(peer))
                    peer->openTxs.insert(Tx{static_cast<std::uint32_t>(to->id)});
            }
            sim.run(1);
 
            // Fork should not happen for 40% or greater overlap
            // Since the overlapped nodes have a UNL that is the union of the
            // two cliques, the maximum sized UNL list is the number of peers
            if (overlap > 0.4 * numPeers)
            {
                BEAST_EXPECT(sim.synchronized());
            }
            else
            {
                // Even if we do fork, there shouldn't be more than 3 ledgers
                // One for cliqueA, one for cliqueB and one for nodes in both
                BEAST_EXPECT(sim.branches() <= 3);
            }
        }
    }
 
    void
    testHubNetwork()
    {
        using namespace csf;
        using namespace std::chrono;
        testcase("hub network");
 
        // Simulate a set of 5 validators that aren't directly connected but
        // rely on a single hub node for communication
 
        ConsensusParms const parms{};
        Sim sim;
        PeerGroup validators = sim.createGroup(5);
        PeerGroup center = sim.createGroup(1);
        validators.trust(validators);
        center.trust(validators);
 
        SimDuration const delay = round<milliseconds>(0.2 * parms.ledgerGRANULARITY);
        validators.connect(center, delay);
 
        center[0]->runAsValidator = false;
 
        // prep round to set initial state.
        sim.run(1);
 
        // everyone submits their own ID as a TX and relay it to peers
        for (Peer* p : validators)
            p->submit(Tx(static_cast<std::uint32_t>(p->id)));
 
        sim.run(1);
 
        // All peers are in sync
        BEAST_EXPECT(sim.synchronized());
    }
 
    // Helper collector for testPreferredByBranch
    // Invasively disconnects network at bad times to cause splits
    struct Disruptor
    {
        csf::PeerGroup& network;
        csf::PeerGroup& groupCfast;
        csf::PeerGroup& groupCsplit;
        csf::SimDuration delay;
        bool reconnected = false;
 
        Disruptor(csf::PeerGroup& net, csf::PeerGroup& c, csf::PeerGroup& split, csf::SimDuration d)
            : network(net), groupCfast(c), groupCsplit(split), delay(d)
        {
        }
 
        template <class E>
        void
        on(csf::PeerID, csf::SimTime, E const&)
        {
        }
 
        void
        on(csf::PeerID who, csf::SimTime, csf::FullyValidateLedger const& e)
        {
            using namespace std::chrono;
            // As soon as the fastC node fully validates C, disconnect
            // ALL c nodes from the network. The fast C node needs to disconnect
            // as well to prevent it from relaying the validations it did see
            if (who == groupCfast[0]->id && e.ledger.seq() == csf::Ledger::Seq{2})
            {
                network.disconnect(groupCsplit);
                network.disconnect(groupCfast);
            }
        }
 
        void
        on(csf::PeerID who, csf::SimTime, csf::AcceptLedger const& e)
        {
            // As soon as anyone generates a child of B or C, reconnect the
            // network so those validations make it through
            if (!reconnected && e.ledger.seq() == csf::Ledger::Seq{3})
            {
                reconnected = true;
                network.connect(groupCsplit, delay);
            }
        }
    };
 
    void
    testPreferredByBranch()
    {
        using namespace csf;
        using namespace std::chrono;
        testcase("preferred by branch");
 
        // Simulate network splits that are prevented from forking when using
        // preferred ledger by trie.  This is a contrived example that involves
        // excessive network splits, but demonstrates the safety improvement
        // from the preferred ledger by trie approach.
 
        // Consider 10 validating nodes that comprise a single common UNL
        // Ledger history:
        // 1:           A
        //            _/ \_
        // 2:         B    C
        //          _/  _/  \_
        // 3:       D   C'  |||||||| (8 different ledgers)
 
        // - All nodes generate the common ledger A
        // - 2 nodes generate B and 8 nodes generate C
        // - Only 1 of the C nodes sees all the C validations and fully
        //   validates C. The rest of the C nodes split at just the right time
        //   such that they never see any C validations but their own.
        // - The C nodes continue and generate 8 different child ledgers.
        // - Meanwhile, the D nodes only saw 1 validation for C and 2
        // validations
        //   for B.
        // - The network reconnects and the validations for generation 3 ledgers
        //   are observed (D and the 8 C's)
        // - In the old approach, 2 votes for D outweighs 1 vote for each C'
        //   so the network would avalanche towards D and fully validate it
        //   EVEN though C was fully validated by one node
        // - In the new approach, 2 votes for D are not enough to outweight the
        //   8 implicit votes for C, so nodes will avalanche to C instead
 
        ConsensusParms const parms{};
        Sim sim;
 
        // Goes A->B->D
        PeerGroup const groupABD = sim.createGroup(2);
        // Single node that initially fully validates C before the split
        PeerGroup groupCfast = sim.createGroup(1);
        // Generates C, but fails to fully validate before the split
        PeerGroup groupCsplit = sim.createGroup(7);
 
        PeerGroup groupNotFastC = groupABD + groupCsplit;
        PeerGroup network = groupABD + groupCsplit + groupCfast;
 
        SimDuration const delay = round<milliseconds>(0.2 * parms.ledgerGRANULARITY);
        SimDuration const fDelay = round<milliseconds>(0.1 * parms.ledgerGRANULARITY);
 
        network.trust(network);
        // C must have a shorter delay to see all the validations before the
        // other nodes
        network.connect(groupCfast, fDelay);
        // The rest of the network is connected at the same speed
        groupNotFastC.connect(groupNotFastC, delay);
 
        Disruptor dc(network, groupCfast, groupCsplit, delay);
        sim.collectors.add(dc);
 
        // Consensus round to generate ledger A
        sim.run(1);
        BEAST_EXPECT(sim.synchronized());
 
        // Next round generates B and C
        // To force B, we inject an extra transaction in to those nodes
        for (Peer* peer : groupABD)
        {
            peer->txInjections.emplace(peer->lastClosedLedger.seq(), Tx{42});
        }
        // The Disruptor will ensure that nodes disconnect before the C
        // validations make it to all but the fastC node
        sim.run(1);
 
        // We are no longer in sync, but have not yet forked:
        // 9 nodes consider A the last fully validated ledger and fastC sees C
        BEAST_EXPECT(!sim.synchronized());
        BEAST_EXPECT(sim.branches() == 1);
 
        //  Run another round to generate the 8 different C' ledgers
        for (Peer* p : network)
            p->submit(Tx(static_cast<std::uint32_t>(p->id)));
        sim.run(1);
 
        // Still not forked
        BEAST_EXPECT(!sim.synchronized());
        BEAST_EXPECT(sim.branches() == 1);
 
        // Disruptor will reconnect all but the fastC node
        sim.run(1);
 
        if (BEAST_EXPECT(sim.branches() == 1))
        {
            BEAST_EXPECT(sim.synchronized());
        }
        else  // old approach caused a fork
        {
            BEAST_EXPECT(sim.branches(groupNotFastC) == 1);
            BEAST_EXPECT(sim.synchronized(groupNotFastC) == 1);
        }
    }
 
    // Helper collector for testPauseForLaggards
    // This will remove the ledgerAccept delay used to
    // initially create the slow vs. fast validator groups.
    struct UndoDelay
    {
        csf::PeerGroup& g;
 
        UndoDelay(csf::PeerGroup& a) : g(a)
        {
        }
 
        template <class E>
        void
        on(csf::PeerID, csf::SimTime, E const&)
        {
        }
 
        void
        on(csf::PeerID who, csf::SimTime, csf::AcceptLedger const& e)
        {
            for (csf::Peer* p : g)
            {
                if (p->id == who)
                    p->delays.ledgerAccept = std::chrono::seconds{0};
            }
        }
    };
 
    void
    testPauseForLaggards()
    {
        using namespace csf;
        using namespace std::chrono;
        testcase("pause for laggards");
 
        // Test that validators that jump ahead of the network slow
        // down.
 
        // We engineer the following validated ledger history scenario:
        //
        //  / --> B1 --> C1 --> ... -> G1  "ahead"
        // A
        //  \ --> B2 --> C2 "behind"
        //
        // After validating a common ledger A, a set of "behind" validators
        // briefly run slower and validate the lower chain of ledgers.
        // The "ahead" validators run normal speed and run ahead validating the
        // upper chain of ledgers.
        //
        // Due to the uncommitted support definition of the preferred branch
        // protocol, even if the "behind" validators are a majority, the "ahead"
        // validators cannot jump to the proper branch until the "behind"
        // validators catch up to the same sequence number. For this test to
        // succeed, the ahead validators need to briefly slow down consensus.
 
        ConsensusParms const parms{};
        Sim sim;
        SimDuration const delay = round<milliseconds>(0.2 * parms.ledgerGRANULARITY);
 
        PeerGroup behind = sim.createGroup(3);
        PeerGroup const ahead = sim.createGroup(2);
        PeerGroup network = ahead + behind;
 
        hash_set<Peer::NodeKey_t> trustedKeys;
        for (Peer const* p : network)
            trustedKeys.insert(p->key);
        for (Peer* p : network)
            p->trustedKeys = trustedKeys;
 
        network.trustAndConnect(network, delay);
 
        // Initial seed round to set prior state
        sim.run(1);
 
        // Have the "behind" group initially take a really long time to
        // accept a ledger after ending deliberation
        for (Peer* p : behind)
            p->delays.ledgerAccept = 20s;
 
        // Use the collector to revert the delay after the single
        // slow ledger is generated
        UndoDelay undoDelay{behind};
        sim.collectors.add(undoDelay);
 
#if 0
        // Have all beast::journal output printed to stdout
        for (Peer* p : network)
            p->sink.threshold(beast::severities::kAll);
 
        // Print ledger accept and fully validated events to stdout
        StreamCollector sc{std::cout};
        sim.collectors.add(sc);
#endif
        // Run the simulation for 100 seconds of simulation time with
        std::chrono::nanoseconds const simDuration = 100s;
 
        // Simulate clients submitting 1 tx every 5 seconds to a random
        // validator
        Rate const rate{1, 5s};
        auto peerSelector = makeSelector(
            network.begin(), network.end(), std::vector<double>(network.size(), 1.), sim.rng);
        auto txSubmitter = makeSubmitter(
            ConstantDistribution{rate.inv()},
            sim.scheduler.now(),
            sim.scheduler.now() + simDuration,
            peerSelector,
            sim.scheduler,
            sim.rng);
 
        // Run simulation
        sim.run(simDuration);
 
        // Verify that the network recovered
        BEAST_EXPECT(sim.synchronized());
    }
 
    void
    testDisputes()
    {
        testcase("disputes");
 
        using namespace csf;
 
        // Test dispute objects directly
        using Dispute = DisputedTx<Tx, PeerID>;
 
        Tx const txTrue{99};
        Tx const txFalse{98};
        Tx const txFollowingTrue{97};
        Tx const txFollowingFalse{96};
        int const numPeers = 100;
        ConsensusParms const p;
        std::size_t peersUnchanged = 0;
 
        auto logs = std::make_unique<Logs>(beast::severities::kError);
        auto j = logs->journal("Test");
        auto clog = std::make_unique<std::stringstream>();
 
        // Three cases:
        // 1 proposing, initial vote yes
        // 2 proposing, initial vote no
        // 3 not proposing, initial vote doesn't matter after the first update,
        // use yes
        {
            Dispute proposingTrue{txTrue.id(), true, numPeers, journal_};
            Dispute proposingFalse{txFalse.id(), false, numPeers, journal_};
            Dispute followingTrue{txFollowingTrue.id(), true, numPeers, journal_};
            Dispute followingFalse{txFollowingFalse.id(), false, numPeers, journal_};
            BEAST_EXPECT(proposingTrue.ID() == 99);
            BEAST_EXPECT(proposingFalse.ID() == 98);
            BEAST_EXPECT(followingTrue.ID() == 97);
            BEAST_EXPECT(followingFalse.ID() == 96);
 
            // Create an even split in the peer votes
            for (int i = 0; i < numPeers; ++i)
            {
                BEAST_EXPECT(proposingTrue.setVote(PeerID(i), i < 50));
                BEAST_EXPECT(proposingFalse.setVote(PeerID(i), i < 50));
                BEAST_EXPECT(followingTrue.setVote(PeerID(i), i < 50));
                BEAST_EXPECT(followingFalse.setVote(PeerID(i), i < 50));
            }
            // Switch the middle vote to match mine
            BEAST_EXPECT(proposingTrue.setVote(PeerID(50), true));
            BEAST_EXPECT(proposingFalse.setVote(PeerID(49), false));
            BEAST_EXPECT(followingTrue.setVote(PeerID(50), true));
            BEAST_EXPECT(followingFalse.setVote(PeerID(49), false));
 
            // no changes yet
            BEAST_EXPECT(proposingTrue.getOurVote() == true);
            BEAST_EXPECT(proposingFalse.getOurVote() == false);
            BEAST_EXPECT(followingTrue.getOurVote() == true);
            BEAST_EXPECT(followingFalse.getOurVote() == false);
            BEAST_EXPECT(!proposingTrue.stalled(p, true, peersUnchanged, j, clog));
            BEAST_EXPECT(!proposingFalse.stalled(p, true, peersUnchanged, j, clog));
            BEAST_EXPECT(!followingTrue.stalled(p, false, peersUnchanged, j, clog));
            BEAST_EXPECT(!followingFalse.stalled(p, false, peersUnchanged, j, clog));
            BEAST_EXPECT(clog->str().empty());
 
            // I'm in the majority, my vote should not change
            BEAST_EXPECT(!proposingTrue.updateVote(5, true, p));
            BEAST_EXPECT(!proposingFalse.updateVote(5, true, p));
            BEAST_EXPECT(!followingTrue.updateVote(5, false, p));
            BEAST_EXPECT(!followingFalse.updateVote(5, false, p));
 
            BEAST_EXPECT(!proposingTrue.updateVote(10, true, p));
            BEAST_EXPECT(!proposingFalse.updateVote(10, true, p));
            BEAST_EXPECT(!followingTrue.updateVote(10, false, p));
            BEAST_EXPECT(!followingFalse.updateVote(10, false, p));
 
            peersUnchanged = 2;
            BEAST_EXPECT(!proposingTrue.stalled(p, true, peersUnchanged, j, clog));
            BEAST_EXPECT(!proposingFalse.stalled(p, true, peersUnchanged, j, clog));
            BEAST_EXPECT(!followingTrue.stalled(p, false, peersUnchanged, j, clog));
            BEAST_EXPECT(!followingFalse.stalled(p, false, peersUnchanged, j, clog));
            BEAST_EXPECT(clog->str().empty());
 
            // Right now, the vote is 51%. The requirement is about to jump to
            // 65%
            BEAST_EXPECT(proposingTrue.updateVote(55, true, p));
            BEAST_EXPECT(!proposingFalse.updateVote(55, true, p));
            BEAST_EXPECT(!followingTrue.updateVote(55, false, p));
            BEAST_EXPECT(!followingFalse.updateVote(55, false, p));
 
            BEAST_EXPECT(proposingTrue.getOurVote() == false);
            BEAST_EXPECT(proposingFalse.getOurVote() == false);
            BEAST_EXPECT(followingTrue.getOurVote() == true);
            BEAST_EXPECT(followingFalse.getOurVote() == false);
            // 16 validators change their vote to match my original vote
            for (int i = 0; i < 16; ++i)
            {
                auto pTrue = PeerID(numPeers - i - 1);
                auto pFalse = PeerID(i);
                BEAST_EXPECT(proposingTrue.setVote(pTrue, true));
                BEAST_EXPECT(proposingFalse.setVote(pFalse, false));
                BEAST_EXPECT(followingTrue.setVote(pTrue, true));
                BEAST_EXPECT(followingFalse.setVote(pFalse, false));
            }
            // The vote should now be 66%, threshold is 65%
            BEAST_EXPECT(proposingTrue.updateVote(60, true, p));
            BEAST_EXPECT(!proposingFalse.updateVote(60, true, p));
            BEAST_EXPECT(!followingTrue.updateVote(60, false, p));
            BEAST_EXPECT(!followingFalse.updateVote(60, false, p));
 
            BEAST_EXPECT(proposingTrue.getOurVote() == true);
            BEAST_EXPECT(proposingFalse.getOurVote() == false);
            BEAST_EXPECT(followingTrue.getOurVote() == true);
            BEAST_EXPECT(followingFalse.getOurVote() == false);
 
            // Threshold jumps to 70%
            BEAST_EXPECT(proposingTrue.updateVote(86, true, p));
            BEAST_EXPECT(!proposingFalse.updateVote(86, true, p));
            BEAST_EXPECT(!followingTrue.updateVote(86, false, p));
            BEAST_EXPECT(!followingFalse.updateVote(86, false, p));
 
            BEAST_EXPECT(proposingTrue.getOurVote() == false);
            BEAST_EXPECT(proposingFalse.getOurVote() == false);
            BEAST_EXPECT(followingTrue.getOurVote() == true);
            BEAST_EXPECT(followingFalse.getOurVote() == false);
 
            // 5 more validators change their vote to match my original vote
            for (int i = 16; i < 21; ++i)
            {
                auto pTrue = PeerID(numPeers - i - 1);
                auto pFalse = PeerID(i);
                BEAST_EXPECT(proposingTrue.setVote(pTrue, true));
                BEAST_EXPECT(proposingFalse.setVote(pFalse, false));
                BEAST_EXPECT(followingTrue.setVote(pTrue, true));
                BEAST_EXPECT(followingFalse.setVote(pFalse, false));
            }
 
            // The vote should now be 71%, threshold is 70%
            BEAST_EXPECT(proposingTrue.updateVote(90, true, p));
            BEAST_EXPECT(!proposingFalse.updateVote(90, true, p));
            BEAST_EXPECT(!followingTrue.updateVote(90, false, p));
            BEAST_EXPECT(!followingFalse.updateVote(90, false, p));
 
            BEAST_EXPECT(proposingTrue.getOurVote() == true);
            BEAST_EXPECT(proposingFalse.getOurVote() == false);
            BEAST_EXPECT(followingTrue.getOurVote() == true);
            BEAST_EXPECT(followingFalse.getOurVote() == false);
 
            // The vote should now be 71%, threshold is 70%
            BEAST_EXPECT(!proposingTrue.updateVote(150, true, p));
            BEAST_EXPECT(!proposingFalse.updateVote(150, true, p));
            BEAST_EXPECT(!followingTrue.updateVote(150, false, p));
            BEAST_EXPECT(!followingFalse.updateVote(150, false, p));
 
            BEAST_EXPECT(proposingTrue.getOurVote() == true);
            BEAST_EXPECT(proposingFalse.getOurVote() == false);
            BEAST_EXPECT(followingTrue.getOurVote() == true);
            BEAST_EXPECT(followingFalse.getOurVote() == false);
 
            // The vote should now be 71%, threshold is 70%
            BEAST_EXPECT(!proposingTrue.updateVote(190, true, p));
            BEAST_EXPECT(!proposingFalse.updateVote(190, true, p));
            BEAST_EXPECT(!followingTrue.updateVote(190, false, p));
            BEAST_EXPECT(!followingFalse.updateVote(190, false, p));
 
            BEAST_EXPECT(proposingTrue.getOurVote() == true);
            BEAST_EXPECT(proposingFalse.getOurVote() == false);
            BEAST_EXPECT(followingTrue.getOurVote() == true);
            BEAST_EXPECT(followingFalse.getOurVote() == false);
 
            peersUnchanged = 3;
            BEAST_EXPECT(!proposingTrue.stalled(p, true, peersUnchanged, j, clog));
            BEAST_EXPECT(!proposingFalse.stalled(p, true, peersUnchanged, j, clog));
            BEAST_EXPECT(!followingTrue.stalled(p, false, peersUnchanged, j, clog));
            BEAST_EXPECT(!followingFalse.stalled(p, false, peersUnchanged, j, clog));
            BEAST_EXPECT(clog->str().empty());
 
            // Threshold jumps to 95%
            BEAST_EXPECT(proposingTrue.updateVote(220, true, p));
            BEAST_EXPECT(!proposingFalse.updateVote(220, true, p));
            BEAST_EXPECT(!followingTrue.updateVote(220, false, p));
            BEAST_EXPECT(!followingFalse.updateVote(220, false, p));
 
            BEAST_EXPECT(proposingTrue.getOurVote() == false);
            BEAST_EXPECT(proposingFalse.getOurVote() == false);
            BEAST_EXPECT(followingTrue.getOurVote() == true);
            BEAST_EXPECT(followingFalse.getOurVote() == false);
 
            // 25 more validators change their vote to match my original vote
            for (int i = 21; i < 46; ++i)
            {
                auto pTrue = PeerID(numPeers - i - 1);
                auto pFalse = PeerID(i);
                BEAST_EXPECT(proposingTrue.setVote(pTrue, true));
                BEAST_EXPECT(proposingFalse.setVote(pFalse, false));
                BEAST_EXPECT(followingTrue.setVote(pTrue, true));
                BEAST_EXPECT(followingFalse.setVote(pFalse, false));
            }
 
            // The vote should now be 96%, threshold is 95%
            BEAST_EXPECT(proposingTrue.updateVote(250, true, p));
            BEAST_EXPECT(!proposingFalse.updateVote(250, true, p));
            BEAST_EXPECT(!followingTrue.updateVote(250, false, p));
            BEAST_EXPECT(!followingFalse.updateVote(250, false, p));
 
            BEAST_EXPECT(proposingTrue.getOurVote() == true);
            BEAST_EXPECT(proposingFalse.getOurVote() == false);
            BEAST_EXPECT(followingTrue.getOurVote() == true);
            BEAST_EXPECT(followingFalse.getOurVote() == false);
 
            for (peersUnchanged = 0; peersUnchanged < 6; ++peersUnchanged)
            {
                BEAST_EXPECT(!proposingTrue.stalled(p, true, peersUnchanged, j, clog));
                BEAST_EXPECT(!proposingFalse.stalled(p, true, peersUnchanged, j, clog));
                BEAST_EXPECT(!followingTrue.stalled(p, false, peersUnchanged, j, clog));
                BEAST_EXPECT(!followingFalse.stalled(p, false, peersUnchanged, j, clog));
                BEAST_EXPECT(clog->str().empty());
            }
 
            auto expectStalled = [this, &clog](
                                     int txid,
                                     bool ourVote,
                                     int ourTime,
                                     int peerTime,
                                     int support,
                                     std::uint32_t line) {
                using namespace std::string_literals;
 
                auto const s = clog->str();
                expect(s.find("stalled"), s, __FILE__, line);
                expect(s.starts_with("Transaction "s + std::to_string(txid)), s, __FILE__, line);
                expect(s.find("voting "s + (ourVote ? "YES" : "NO")) != s.npos, s, __FILE__, line);
                expect(
                    s.find("for "s + std::to_string(ourTime) + " rounds."s) != s.npos,
                    s,
                    __FILE__,
                    line);
                expect(
                    s.find("votes in "s + std::to_string(peerTime) + " rounds.") != s.npos,
                    s,
                    __FILE__,
                    line);
                expect(
                    s.ends_with("has "s + std::to_string(support) + "% support. "s),
                    s,
                    __FILE__,
                    line);
                clog = std::make_unique<std::stringstream>();
            };
 
            for (int i = 0; i < 1; ++i)
            {
                BEAST_EXPECT(!proposingTrue.updateVote(250 + (10 * i), true, p));
                BEAST_EXPECT(!proposingFalse.updateVote(250 + (10 * i), true, p));
                BEAST_EXPECT(!followingTrue.updateVote(250 + (10 * i), false, p));
                BEAST_EXPECT(!followingFalse.updateVote(250 + (10 * i), false, p));
 
                BEAST_EXPECT(proposingTrue.getOurVote() == true);
                BEAST_EXPECT(proposingFalse.getOurVote() == false);
                BEAST_EXPECT(followingTrue.getOurVote() == true);
                BEAST_EXPECT(followingFalse.getOurVote() == false);
 
                // true vote has changed recently, so not stalled
                BEAST_EXPECT(!proposingTrue.stalled(p, true, 0, j, clog));
                BEAST_EXPECT(clog->str().empty());
                // remaining votes have been unchanged in so long that we only
                // need to hit the second round at 95% to be stalled, regardless
                // of peers
                BEAST_EXPECT(proposingFalse.stalled(p, true, 0, j, clog));
                expectStalled(98, false, 11, 0, 2, __LINE__);
                BEAST_EXPECT(followingTrue.stalled(p, false, 0, j, clog));
                expectStalled(97, true, 11, 0, 97, __LINE__);
                BEAST_EXPECT(followingFalse.stalled(p, false, 0, j, clog));
                expectStalled(96, false, 11, 0, 3, __LINE__);
 
                // true vote has changed recently, so not stalled
                BEAST_EXPECT(!proposingTrue.stalled(p, true, peersUnchanged, j, clog));
                BEAST_EXPECTS(clog->str().empty(), clog->str());
                // remaining votes have been unchanged in so long that we only
                // need to hit the second round at 95% to be stalled, regardless
                // of peers
                BEAST_EXPECT(proposingFalse.stalled(p, true, peersUnchanged, j, clog));
                expectStalled(98, false, 11, 6, 2, __LINE__);
                BEAST_EXPECT(followingTrue.stalled(p, false, peersUnchanged, j, clog));
                expectStalled(97, true, 11, 6, 97, __LINE__);
                BEAST_EXPECT(followingFalse.stalled(p, false, peersUnchanged, j, clog));
                expectStalled(96, false, 11, 6, 3, __LINE__);
            }
            for (int i = 1; i < 3; ++i)
            {
                BEAST_EXPECT(!proposingTrue.updateVote(250 + (10 * i), true, p));
                BEAST_EXPECT(!proposingFalse.updateVote(250 + (10 * i), true, p));
                BEAST_EXPECT(!followingTrue.updateVote(250 + (10 * i), false, p));
                BEAST_EXPECT(!followingFalse.updateVote(250 + (10 * i), false, p));
 
                BEAST_EXPECT(proposingTrue.getOurVote() == true);
                BEAST_EXPECT(proposingFalse.getOurVote() == false);
                BEAST_EXPECT(followingTrue.getOurVote() == true);
                BEAST_EXPECT(followingFalse.getOurVote() == false);
 
                // true vote changed 2 rounds ago, and peers are changing, so
                // not stalled
                BEAST_EXPECT(!proposingTrue.stalled(p, true, 0, j, clog));
                BEAST_EXPECTS(clog->str().empty(), clog->str());
                // still stalled
                BEAST_EXPECT(proposingFalse.stalled(p, true, 0, j, clog));
                expectStalled(98, false, 11 + i, 0, 2, __LINE__);
                BEAST_EXPECT(followingTrue.stalled(p, false, 0, j, clog));
                expectStalled(97, true, 11 + i, 0, 97, __LINE__);
                BEAST_EXPECT(followingFalse.stalled(p, false, 0, j, clog));
                expectStalled(96, false, 11 + i, 0, 3, __LINE__);
 
                // true vote changed 2 rounds ago, and peers are NOT changing,
                // so stalled
                BEAST_EXPECT(proposingTrue.stalled(p, true, peersUnchanged, j, clog));
                expectStalled(99, true, 1 + i, 6, 97, __LINE__);
                // still stalled
                BEAST_EXPECT(proposingFalse.stalled(p, true, peersUnchanged, j, clog));
                expectStalled(98, false, 11 + i, 6, 2, __LINE__);
                BEAST_EXPECT(followingTrue.stalled(p, false, peersUnchanged, j, clog));
                expectStalled(97, true, 11 + i, 6, 97, __LINE__);
                BEAST_EXPECT(followingFalse.stalled(p, false, peersUnchanged, j, clog));
                expectStalled(96, false, 11 + i, 6, 3, __LINE__);
            }
            for (int i = 3; i < 5; ++i)
            {
                BEAST_EXPECT(!proposingTrue.updateVote(250 + (10 * i), true, p));
                BEAST_EXPECT(!proposingFalse.updateVote(250 + (10 * i), true, p));
                BEAST_EXPECT(!followingTrue.updateVote(250 + (10 * i), false, p));
                BEAST_EXPECT(!followingFalse.updateVote(250 + (10 * i), false, p));
 
                BEAST_EXPECT(proposingTrue.getOurVote() == true);
                BEAST_EXPECT(proposingFalse.getOurVote() == false);
                BEAST_EXPECT(followingTrue.getOurVote() == true);
                BEAST_EXPECT(followingFalse.getOurVote() == false);
 
                BEAST_EXPECT(proposingTrue.stalled(p, true, 0, j, clog));
                expectStalled(99, true, 1 + i, 0, 97, __LINE__);
                BEAST_EXPECT(proposingFalse.stalled(p, true, 0, j, clog));
                expectStalled(98, false, 11 + i, 0, 2, __LINE__);
                BEAST_EXPECT(followingTrue.stalled(p, false, 0, j, clog));
                expectStalled(97, true, 11 + i, 0, 97, __LINE__);
                BEAST_EXPECT(followingFalse.stalled(p, false, 0, j, clog));
                expectStalled(96, false, 11 + i, 0, 3, __LINE__);
 
                BEAST_EXPECT(proposingTrue.stalled(p, true, peersUnchanged, j, clog));
                expectStalled(99, true, 1 + i, 6, 97, __LINE__);
                BEAST_EXPECT(proposingFalse.stalled(p, true, peersUnchanged, j, clog));
                expectStalled(98, false, 11 + i, 6, 2, __LINE__);
                BEAST_EXPECT(followingTrue.stalled(p, false, peersUnchanged, j, clog));
                expectStalled(97, true, 11 + i, 6, 97, __LINE__);
                BEAST_EXPECT(followingFalse.stalled(p, false, peersUnchanged, j, clog));
                expectStalled(96, false, 11 + i, 6, 3, __LINE__);
            }
        }
    }
 
    void
    run() override
    {
        testShouldCloseLedger();
        testCheckConsensus();
 
        testStandalone();
        testPeersAgree();
        testSlowPeers();
        testCloseTimeDisagree();
        testWrongLCL();
        testConsensusCloseTimeRounding();
        testFork();
        testHubNetwork();
        testPreferredByBranch();
        testPauseForLaggards();
        testDisputes();
    }
};
 
BEAST_DEFINE_TESTSUITE(Consensus, consensus, xrpl);
}  // namespace test
}  // namespace xrpl