pow_tests.cpp

// Copyright (c) 2015 The Bitcoin Core developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <chain.h>
#include <chainparams.h>
#include <config.h>
#include <consensus/activation.h>
#include <pow.h>
#include <random.h>
#include <tinyformat.h>
#include <util/system.h>

#include <test/setup_common.h>

#include <boost/test/unit_test.hpp>

#include <cmath>
#include <memory>
#include <string>

BOOST_FIXTURE_TEST_SUITE(pow_tests, TestingSetup)

/* Test calculation of next difficulty target with no constraints applying */

BOOST_AUTO_TEST_CASE(get_next_work) {
    DummyConfig config(CBaseChainParams::MAIN);

    int64_t nLastRetargetTime = 1261130161; // Block #30240
    CBlockIndex pindexLast;
    pindexLast.nHeight = 32255;
    pindexLast.nTime = 1261152739; // Block #32255
    pindexLast.nBits = 0x1d00ffff;
    BOOST_CHECK_EQUAL(
        CalculateNextWorkRequired(&pindexLast, nLastRetargetTime,
                                  config.GetChainParams().GetConsensus()),
        473956288);
}

/* Test the constraint on the upper bound for next work */
BOOST_AUTO_TEST_CASE(get_next_work_pow_limit) {
    DummyConfig config(CBaseChainParams::MAIN);

    int64_t nLastRetargetTime = 1231006505; // Block #0
    CBlockIndex pindexLast;
    pindexLast.nHeight = 2015;
    pindexLast.nTime = 1233061996; // Block #2015
    pindexLast.nBits = 0x1d00ffff;

    BOOST_CHECK_EQUAL(
        CalculateNextWorkRequired(&pindexLast, nLastRetargetTime,
                                  config.GetChainParams().GetConsensus()),
        0x1d00ffffU);
}

/* Test the constraint on the lower bound for actual time taken */
BOOST_AUTO_TEST_CASE(get_next_work_lower_limit_actual) {
    DummyConfig config(CBaseChainParams::MAIN);

    int64_t nLastRetargetTime = 1279008237; // Block #66528
    CBlockIndex pindexLast;
    pindexLast.nHeight = 68543;
    pindexLast.nTime = 1279297671; // Block #68543
    pindexLast.nBits = 0x1c05a3f4;

    BOOST_CHECK_EQUAL(
        CalculateNextWorkRequired(&pindexLast, nLastRetargetTime,
                                  config.GetChainParams().GetConsensus()),
        469938949);
}

/* Test the constraint on the upper bound for actual time taken */
BOOST_AUTO_TEST_CASE(get_next_work_upper_limit_actual) {
    DummyConfig config(CBaseChainParams::MAIN);

    int64_t nLastRetargetTime = 1263163443; // NOTE: Not an actual block time
    CBlockIndex pindexLast;
    pindexLast.nHeight = 46367;
    pindexLast.nTime = 1269211443; // Block #46367
    pindexLast.nBits = 0x1c387f6f;

    BOOST_CHECK_EQUAL(
        CalculateNextWorkRequired(&pindexLast, nLastRetargetTime,
                                  config.GetChainParams().GetConsensus()),
        0x1d00e1fdU);
}

BOOST_AUTO_TEST_CASE(GetBlockProofEquivalentTime_test) {
    DummyConfig config(CBaseChainParams::MAIN);

    std::vector<CBlockIndex> blocks(10000);
    for (int i = 0; i < 10000; i++) {
        blocks[i].pprev = i ? &blocks[i - 1] : nullptr;
        blocks[i].nHeight = i;
        blocks[i].nTime =
            1269211443 +
            i * config.GetChainParams().GetConsensus().nPowTargetSpacing;
        blocks[i].nBits = 0x207fffff; /* target 0x7fffff000... */
        blocks[i].nChainWork =
            i ? blocks[i - 1].nChainWork + GetBlockProof(blocks[i])
              : arith_uint256(0);
    }

    for (int j = 0; j < 1000; j++) {
        CBlockIndex *p1 = &blocks[InsecureRandRange(10000)];
        CBlockIndex *p2 = &blocks[InsecureRandRange(10000)];
        CBlockIndex *p3 = &blocks[InsecureRandRange(10000)];

        int64_t tdiff = GetBlockProofEquivalentTime(
            *p1, *p2, *p3, config.GetChainParams().GetConsensus());
        BOOST_CHECK_EQUAL(tdiff, p1->GetBlockTime() - p2->GetBlockTime());
    }
}
 
BOOST_AUTO_TEST_CASE(CheckProofOfWork_test_negative_target)
{
DummyConfig config(CBaseChainParams::MAIN);
    uint256 hash;
    unsigned int nBits;
    nBits = UintToArith256(config.GetChainParams().GetConsensus().powLimit).GetCompact(true);
    hash.SetHex("0x1");
    BOOST_CHECK(!CheckProofOfWork(BlockHash(hash), nBits, config.GetChainParams().GetConsensus()));
}

BOOST_AUTO_TEST_CASE(CheckProofOfWork_test_overflow_target)
{
    DummyConfig config(CBaseChainParams::MAIN);
    uint256 hash;
    unsigned int nBits{~0x00800000U};
    hash.SetHex("0x1");
    BOOST_CHECK(!CheckProofOfWork(BlockHash(hash), nBits, config.GetChainParams().GetConsensus()));
}

BOOST_AUTO_TEST_CASE(CheckProofOfWork_test_too_easy_target)
{
    DummyConfig config(CBaseChainParams::MAIN);
    uint256 hash;
    unsigned int nBits;
    arith_uint256 nBits_arith = UintToArith256(config.GetChainParams().GetConsensus().powLimit);
    nBits_arith *= 2;
    nBits = nBits_arith.GetCompact();
    hash.SetHex("0x1");
    BOOST_CHECK(!CheckProofOfWork(BlockHash(hash), nBits, config.GetChainParams().GetConsensus()));
}

BOOST_AUTO_TEST_CASE(CheckProofOfWork_test_biger_hash_than_target)
{ 
    DummyConfig config(CBaseChainParams::MAIN);
    uint256 hash;
    unsigned int nBits;
    arith_uint256 hash_arith = UintToArith256(config.GetChainParams().GetConsensus().powLimit);
    nBits = hash_arith.GetCompact();
    hash_arith *= 2; // hash > nBits
    hash = ArithToUint256(hash_arith);
    BOOST_CHECK(!CheckProofOfWork(BlockHash(hash), nBits, config.GetChainParams().GetConsensus()));
}

BOOST_AUTO_TEST_CASE(CheckProofOfWork_test_zero_target)
{
    DummyConfig config(CBaseChainParams::MAIN);
    uint256 hash;
    unsigned int nBits;
    arith_uint256 hash_arith{0};
    nBits = hash_arith.GetCompact();
    hash = ArithToUint256(hash_arith);
    BOOST_CHECK(!CheckProofOfWork(BlockHash(hash), nBits, config.GetChainParams().GetConsensus()));
}
 
double TargetFromBits(const uint32_t nBits) {
    return (nBits & 0xff'ff'ff) * pow(256, (nBits >> 24)-3);
}
 
std::string StrPrintCalcArgs(const arith_uint256 refTarget,
                             const int64_t targetSpacing,
                             const int64_t timeDiff,
                             const int64_t heightDiff,
                             const arith_uint256 expectedTarget,
                             const uint32_t expectednBits) {
    return strprintf("\n"
                     "ref=         %s\n"
                     "spacing=     %d\n"
                     "timeDiff=    %d\n"
                     "heightDiff=  %d\n"
                     "expTarget=   %s\n"
                     "exp nBits=   0x%08x\n",
                     refTarget.ToString(),
                     targetSpacing,
                     timeDiff,
                     heightDiff,
                     expectedTarget.ToString(),
                     expectednBits);
}
 
BOOST_AUTO_TEST_SUITE_END()