versionbits_tests.cpp

// Copyright (c) 2014-2016 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include "chaincontrol/chain.h"
#include "framework/versionbits.h"
#include "test/test_bitcoin.h"
#include "config/chainparams.h"
#include "block/validation.h"
#include "config/params.h"

#include <boost/test/unit_test.hpp>

/* Define a virtual block time, one block per 10 minutes after Nov 14 2014, 0:55:36am */
int32_t TestTime(int nHeight)
{
    return 1415926536 + 600 * nHeight;
}

static const Consensus::Params paramsDummy = Consensus::Params();

class TestConditionChecker : public AbstractThresholdConditionChecker
{
private:
    mutable ThresholdConditionCache cache;

public:
    int64_t BeginTime(const Consensus::Params &params) const override
    {
        return TestTime(10000);
    }

    int64_t EndTime(const Consensus::Params &params) const override
    {
        return TestTime(20000);
    }

    int Period(const Consensus::Params &params) const override
    {
        return 1000;
    }

    int Threshold(const Consensus::Params &params) const override
    {
        return 900;
    }

    bool Condition(const CBlockIndex *pindex, const Consensus::Params &params) const override
    {
        return (pindex->nVersion & 0x100);
    }

    ThresholdState GetStateFor(const CBlockIndex *pindexPrev) const
    {
        return AbstractThresholdConditionChecker::GetStateFor(pindexPrev, paramsDummy, cache);
    }

    int GetStateSinceHeightFor(const CBlockIndex *pindexPrev) const
    {
        return AbstractThresholdConditionChecker::GetStateSinceHeightFor(pindexPrev, paramsDummy, cache);
    }
};

#define CHECKERS 6

class VersionBitsTester
{
    // A fake blockchain
    std::vector<CBlockIndex *> vpblock;

    // 6 independent checkers for the same bit.
    // The first one performs all checks, the second only 50%, the third only 25%, etc...
    // This is to test whether lack of cached information leads to the same results.
    TestConditionChecker checker[CHECKERS];

    // Test counter (to identify failures)
    int num;

public:
    VersionBitsTester() : num(0)
    {
    }

    VersionBitsTester &Reset()
    {
        for (unsigned int i = 0; i < vpblock.size(); i++)
        {
            delete vpblock[i];
        }
        for (unsigned int i = 0; i < CHECKERS; i++)
        {
            checker[i] = TestConditionChecker();
        }
        vpblock.clear();
        return *this;
    }

    ~VersionBitsTester()
    {
        Reset();
    }

    VersionBitsTester &Mine(unsigned int height, int32_t nTime, int32_t nVersion)
    {
        while (vpblock.size() < height)
        {
            CBlockIndex *pindex = new CBlockIndex();
            pindex->nHeight = vpblock.size();
            pindex->pprev = vpblock.size() > 0 ? vpblock.back() : nullptr;
            pindex->nTime = nTime;
            pindex->nVersion = nVersion;
            pindex->BuildSkip();
            vpblock.push_back(pindex);
        }
        return *this;
    }

    VersionBitsTester &TestStateSinceHeight(int height)
    {
        for (int i = 0; i < CHECKERS; i++)
        {
            if (InsecureRandBits(i) == 0)
            {
                BOOST_CHECK_MESSAGE(
                        checker[i].GetStateSinceHeightFor(vpblock.empty() ? nullptr : vpblock.back()) == height,
                        strprintf("Test %i for StateSinceHeight", num));
            }
        }
        num++;
        return *this;
    }

    VersionBitsTester &TestDefined()
    {
        for (int i = 0; i < CHECKERS; i++)
        {
            if (InsecureRandBits(i) == 0)
            {
                BOOST_CHECK_MESSAGE(
                        checker[i].GetStateFor(vpblock.empty() ? nullptr : vpblock.back()) == THRESHOLD_DEFINED,
                        strprintf("Test %i for DEFINED", num));
            }
        }
        num++;
        return *this;
    }

    VersionBitsTester &TestStarted()
    {
        for (int i = 0; i < CHECKERS; i++)
        {
            if (InsecureRandBits(i) == 0)
            {
                BOOST_CHECK_MESSAGE(
                        checker[i].GetStateFor(vpblock.empty() ? nullptr : vpblock.back()) == THRESHOLD_STARTED,
                        strprintf("Test %i for STARTED", num));
            }
        }
        num++;
        return *this;
    }

    VersionBitsTester &TestLockedIn()
    {
        for (int i = 0; i < CHECKERS; i++)
        {
            if (InsecureRandBits(i) == 0)
            {
                BOOST_CHECK_MESSAGE(
                        checker[i].GetStateFor(vpblock.empty() ? nullptr : vpblock.back()) == THRESHOLD_LOCKED_IN,
                        strprintf("Test %i for LOCKED_IN", num));
            }
        }
        num++;
        return *this;
    }

    VersionBitsTester &TestActive()
    {
        for (int i = 0; i < CHECKERS; i++)
        {
            if (InsecureRandBits(i) == 0)
            {
                BOOST_CHECK_MESSAGE(
                        checker[i].GetStateFor(vpblock.empty() ? nullptr : vpblock.back()) == THRESHOLD_ACTIVE,
                        strprintf("Test %i for ACTIVE", num));
            }
        }
        num++;
        return *this;
    }

    VersionBitsTester &TestFailed()
    {
        for (int i = 0; i < CHECKERS; i++)
        {
            if (InsecureRandBits(i) == 0)
            {
                BOOST_CHECK_MESSAGE(
                        checker[i].GetStateFor(vpblock.empty() ? nullptr : vpblock.back()) == THRESHOLD_FAILED,
                        strprintf("Test %i for FAILED", num));
            }
        }
        num++;
        return *this;
    }

    CBlockIndex *Tip()
    {
        return vpblock.size() ? vpblock.back() : nullptr;
    }
};

BOOST_FIXTURE_TEST_SUITE(versionbits_tests, TestingSetup)

    BOOST_AUTO_TEST_CASE(versionbits_test)
    {
        for (int i = 0; i < 64; i++)
        {
            // DEFINED -> FAILED
            VersionBitsTester().TestDefined().TestStateSinceHeight(0)
                    .Mine(1, TestTime(1), 0x100).TestDefined().TestStateSinceHeight(0)
                    .Mine(11, TestTime(11), 0x100).TestDefined().TestStateSinceHeight(0)
                    .Mine(989, TestTime(989), 0x100).TestDefined().TestStateSinceHeight(0)
                    .Mine(999, TestTime(20000), 0x100).TestDefined().TestStateSinceHeight(0)
                    .Mine(1000, TestTime(20000), 0x100).TestFailed().TestStateSinceHeight(1000)
                    .Mine(1999, TestTime(30001), 0x100).TestFailed().TestStateSinceHeight(1000)
                    .Mine(2000, TestTime(30002), 0x100).TestFailed().TestStateSinceHeight(1000)
                    .Mine(2001, TestTime(30003), 0x100).TestFailed().TestStateSinceHeight(1000)
                    .Mine(2999, TestTime(30004), 0x100).TestFailed().TestStateSinceHeight(1000)
                    .Mine(3000, TestTime(30005), 0x100).TestFailed().TestStateSinceHeight(1000)

                            // DEFINED -> STARTED -> FAILED
                    .Reset().TestDefined().TestStateSinceHeight(0)
                    .Mine(1, TestTime(1), 0).TestDefined().TestStateSinceHeight(0)
                    .Mine(1000, TestTime(10000) - 1, 0x100).TestDefined().TestStateSinceHeight(
                            0) // One second more and it would be defined
                    .Mine(2000, TestTime(10000), 0x100).TestStarted().TestStateSinceHeight(
                            2000) // So that's what happens the next period
                    .Mine(2051, TestTime(10010), 0).TestStarted().TestStateSinceHeight(2000) // 51 old blocks
                    .Mine(2950, TestTime(10020), 0x100).TestStarted().TestStateSinceHeight(2000) // 899 new blocks
                    .Mine(3000, TestTime(20000), 0).TestFailed().TestStateSinceHeight(
                            3000) // 50 old blocks (so 899 out of the past 1000)
                    .Mine(4000, TestTime(20010), 0x100).TestFailed().TestStateSinceHeight(3000)

                            // DEFINED -> STARTED -> FAILED while threshold reached
                    .Reset().TestDefined().TestStateSinceHeight(0)
                    .Mine(1, TestTime(1), 0).TestDefined().TestStateSinceHeight(0)
                    .Mine(1000, TestTime(10000) - 1, 0x101).TestDefined().TestStateSinceHeight(
                            0) // One second more and it would be defined
                    .Mine(2000, TestTime(10000), 0x101).TestStarted().TestStateSinceHeight(
                            2000) // So that's what happens the next period
                    .Mine(2999, TestTime(30000), 0x100).TestStarted().TestStateSinceHeight(2000) // 999 new blocks
                    .Mine(3000, TestTime(30000), 0x100).TestFailed().TestStateSinceHeight(
                            3000) // 1 new block (so 1000 out of the past 1000 are new)
                    .Mine(3999, TestTime(30001), 0).TestFailed().TestStateSinceHeight(3000)
                    .Mine(4000, TestTime(30002), 0).TestFailed().TestStateSinceHeight(3000)
                    .Mine(14333, TestTime(30003), 0).TestFailed().TestStateSinceHeight(3000)
                    .Mine(24000, TestTime(40000), 0).TestFailed().TestStateSinceHeight(3000)

                            // DEFINED -> STARTED -> LOCKEDIN at the last minute -> ACTIVE
                    .Reset().TestDefined()
                    .Mine(1, TestTime(1), 0).TestDefined().TestStateSinceHeight(0)
                    .Mine(1000, TestTime(10000) - 1, 0x101).TestDefined().TestStateSinceHeight(
                            0) // One second more and it would be defined
                    .Mine(2000, TestTime(10000), 0x101).TestStarted().TestStateSinceHeight(
                            2000) // So that's what happens the next period
                    .Mine(2050, TestTime(10010), 0x200).TestStarted().TestStateSinceHeight(2000) // 50 old blocks
                    .Mine(2950, TestTime(10020), 0x100).TestStarted().TestStateSinceHeight(2000) // 900 new blocks
                    .Mine(2999, TestTime(19999), 0x200).TestStarted().TestStateSinceHeight(2000) // 49 old blocks
                    .Mine(3000, TestTime(29999), 0x200).TestLockedIn().TestStateSinceHeight(
                            3000) // 1 old block (so 900 out of the past 1000)
                    .Mine(3999, TestTime(30001), 0).TestLockedIn().TestStateSinceHeight(3000)
                    .Mine(4000, TestTime(30002), 0).TestActive().TestStateSinceHeight(4000)
                    .Mine(14333, TestTime(30003), 0).TestActive().TestStateSinceHeight(4000)
                    .Mine(24000, TestTime(40000), 0).TestActive().TestStateSinceHeight(4000)

                            // DEFINED multiple periods -> STARTED multiple periods -> FAILED
                    .Reset().TestDefined().TestStateSinceHeight(0)
                    .Mine(999, TestTime(999), 0).TestDefined().TestStateSinceHeight(0)
                    .Mine(1000, TestTime(1000), 0).TestDefined().TestStateSinceHeight(0)
                    .Mine(2000, TestTime(2000), 0).TestDefined().TestStateSinceHeight(0)
                    .Mine(3000, TestTime(10000), 0).TestStarted().TestStateSinceHeight(3000)
                    .Mine(4000, TestTime(10000), 0).TestStarted().TestStateSinceHeight(3000)
                    .Mine(5000, TestTime(10000), 0).TestStarted().TestStateSinceHeight(3000)
                    .Mine(6000, TestTime(20000), 0).TestFailed().TestStateSinceHeight(6000)
                    .Mine(7000, TestTime(20000), 0x100).TestFailed().TestStateSinceHeight(6000);
        }

        // Sanity checks of version bit deployments
        const auto chainParams = CreateChainParams(CChainParams::MAIN);
        const Consensus::Params &mainnetParams = chainParams->GetConsensus();
        for (int i = 0; i < (int)Consensus::MAX_VERSION_BITS_DEPLOYMENTS; i++)
        {
            uint32_t bitmask = VersionBitsMask(mainnetParams, (Consensus::DeploymentPos)i);
            // Make sure that no deployment tries to set an invalid bit.
            BOOST_CHECK_EQUAL(bitmask & ~(uint32_t)VERSIONBITS_TOP_MASK, bitmask);

            // Verify that the deployment windows of different deployment using the
            // same bit are disjoint.
            // This test may need modification at such time as a new deployment
            // is proposed that reuses the bit of an activated soft fork, before the
            // end time of that soft fork.  (Alternatively, the end time of that
            // activated soft fork could be later changed to be earlier to avoid
            // overlap.)
            for (int j = i + 1; j < (int)Consensus::MAX_VERSION_BITS_DEPLOYMENTS; j++)
            {
                if (VersionBitsMask(mainnetParams, (Consensus::DeploymentPos)j) == bitmask)
                {
                    BOOST_CHECK(mainnetParams.vDeployments[j].nStartTime > mainnetParams.vDeployments[i].nTimeout ||
                                mainnetParams.vDeployments[i].nStartTime > mainnetParams.vDeployments[j].nTimeout);
                }
            }
        }
    }

    BOOST_AUTO_TEST_CASE(versionbits_computeblockversion)
    {
        // Check that ComputeBlockVersion will set the appropriate bit correctly
        // on mainnet.
        const auto chainParams = CreateChainParams(CChainParams::MAIN);
        const Consensus::Params &mainnetParams = chainParams->GetConsensus();

        // Use the TESTDUMMY deployment for testing purposes.
        int64_t bit = mainnetParams.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].bit;
        int64_t nStartTime = mainnetParams.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nStartTime;
        int64_t nTimeout = mainnetParams.vDeployments[Consensus::DEPLOYMENT_TESTDUMMY].nTimeout;

        assert(nStartTime < nTimeout);

        // In the first chain, test that the bit is set by CBV until it has failed.
        // In the second chain, test the bit is set by CBV while STARTED and
        // LOCKED-IN, and then no longer set while ACTIVE.
        VersionBitsTester firstChain, secondChain;

        // Start generating blocks before nStartTime
        int64_t nTime = nStartTime - 1;

        // Before MedianTimePast of the chain has crossed nStartTime, the bit
        // should not be set.
        CBlockIndex *lastBlock = nullptr;
        lastBlock = firstChain.Mine(2016, nTime, VERSIONBITS_LAST_OLD_BLOCK_VERSION).Tip();
        BOOST_CHECK_EQUAL(ComputeBlockVersion(lastBlock, mainnetParams) & (1 << bit), 0);

        // Mine 2011 more blocks at the old time, and check that CBV isn't setting the bit yet.
        for (int i = 1; i < 2012; i++)
        {
            lastBlock = firstChain.Mine(2016 + i, nTime, VERSIONBITS_LAST_OLD_BLOCK_VERSION).Tip();
            // This works because VERSIONBITS_LAST_OLD_BLOCK_VERSION happens
            // to be 4, and the bit we're testing happens to be bit 28.
            BOOST_CHECK_EQUAL(ComputeBlockVersion(lastBlock, mainnetParams) & (1 << bit), 0);
        }
        // Now mine 5 more blocks at the start time -- MTP should not have passed yet, so
        // CBV should still not yet set the bit.
        nTime = nStartTime;
        for (int i = 2012; i <= 2016; i++)
        {
            lastBlock = firstChain.Mine(2016 + i, nTime, VERSIONBITS_LAST_OLD_BLOCK_VERSION).Tip();
            BOOST_CHECK_EQUAL(ComputeBlockVersion(lastBlock, mainnetParams) & (1 << bit), 0);
        }

        // Advance to the next period and transition to STARTED,
        lastBlock = firstChain.Mine(6048, nTime, VERSIONBITS_LAST_OLD_BLOCK_VERSION).Tip();
        // so ComputeBlockVersion should now set the bit,
        BOOST_CHECK((ComputeBlockVersion(lastBlock, mainnetParams) & (1 << bit)) != 0);
        // and should also be using the VERSIONBITS_TOP_BITS.
        BOOST_CHECK_EQUAL(ComputeBlockVersion(lastBlock, mainnetParams) & VERSIONBITS_TOP_MASK, VERSIONBITS_TOP_BITS);

        // Check that ComputeBlockVersion will set the bit until nTimeout
        nTime += 600;
        int blocksToMine = 4032; // test blocks for up to 2 time periods
        int nHeight = 6048;
        // These blocks are all before nTimeout is reached.
        while (nTime < nTimeout && blocksToMine > 0)
        {
            lastBlock = firstChain.Mine(nHeight + 1, nTime, VERSIONBITS_LAST_OLD_BLOCK_VERSION).Tip();
            BOOST_CHECK((ComputeBlockVersion(lastBlock, mainnetParams) & (1 << bit)) != 0);
            BOOST_CHECK_EQUAL(ComputeBlockVersion(lastBlock, mainnetParams) & VERSIONBITS_TOP_MASK,
                              VERSIONBITS_TOP_BITS);
            blocksToMine--;
            nTime += 600;
            nHeight += 1;
        }

        nTime = nTimeout;
        // FAILED is only triggered at the end of a period, so CBV should be setting
        // the bit until the period transition.
        for (int i = 0; i < 2015; i++)
        {
            lastBlock = firstChain.Mine(nHeight + 1, nTime, VERSIONBITS_LAST_OLD_BLOCK_VERSION).Tip();
            BOOST_CHECK((ComputeBlockVersion(lastBlock, mainnetParams) & (1 << bit)) != 0);
            nHeight += 1;
        }
        // The next block should trigger no longer setting the bit.
        lastBlock = firstChain.Mine(nHeight + 1, nTime, VERSIONBITS_LAST_OLD_BLOCK_VERSION).Tip();
        BOOST_CHECK_EQUAL(ComputeBlockVersion(lastBlock, mainnetParams) & (1 << bit), 0);

        // On a new chain:
        // verify that the bit will be set after lock-in, and then stop being set
        // after activation.
        nTime = nStartTime;

        // Mine one period worth of blocks, and check that the bit will be on for the
        // next period.
        lastBlock = secondChain.Mine(2016, nStartTime, VERSIONBITS_LAST_OLD_BLOCK_VERSION).Tip();
        BOOST_CHECK((ComputeBlockVersion(lastBlock, mainnetParams) & (1 << bit)) != 0);

        // Mine another period worth of blocks, signaling the new bit.
        lastBlock = secondChain.Mine(4032, nStartTime, VERSIONBITS_TOP_BITS | (1 << bit)).Tip();
        // After one period of setting the bit on each block, it should have locked in.
        // We keep setting the bit for one more period though, until activation.
        BOOST_CHECK((ComputeBlockVersion(lastBlock, mainnetParams) & (1 << bit)) != 0);

        // Now check that we keep mining the block until the end of this period, and
        // then stop at the beginning of the next period.
        lastBlock = secondChain.Mine(6047, nStartTime, VERSIONBITS_LAST_OLD_BLOCK_VERSION).Tip();
        BOOST_CHECK((ComputeBlockVersion(lastBlock, mainnetParams) & (1 << bit)) != 0);
        lastBlock = secondChain.Mine(6048, nStartTime, VERSIONBITS_LAST_OLD_BLOCK_VERSION).Tip();
        BOOST_CHECK_EQUAL(ComputeBlockVersion(lastBlock, mainnetParams) & (1 << bit), 0);

        // Finally, verify that after a soft fork has activated, CBV no longer uses
        // VERSIONBITS_LAST_OLD_BLOCK_VERSION.
        //BOOST_CHECK_EQUAL(ComputeBlockVersion(lastBlock, mainnetParams) & VERSIONBITS_TOP_MASK, VERSIONBITS_TOP_BITS);
    }


BOOST_AUTO_TEST_SUITE_END()