71 lines
3.3 KiB
C++
71 lines
3.3 KiB
C++
#include <gtest/gtest.h>
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#include <chain.h>
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#include <chainparams.h>
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#include <pow.h>
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#include <random.h>
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TEST(PoW, DifficultyAveraging) {
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SelectParams(CBaseChainParams::MAIN);
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const Consensus::Params& params = Params().GetConsensus();
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size_t lastBlk = 2*params.nPowAveragingWindow;
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size_t firstBlk = lastBlk - params.nPowAveragingWindow;
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// Start with blocks evenly-spaced and equal difficulty
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std::vector<CBlockIndex> blocks(lastBlk+1);
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for (int i = 0; i <= lastBlk; i++) {
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blocks[i].pprev = i ? &blocks[i - 1] : nullptr;
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blocks[i].nHeight = i;
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blocks[i].nTime = 1269211443 + i * params.nPowTargetSpacing;
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blocks[i].nBits = 0x1e7fffff; /* target 0x007fffff000... */
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blocks[i].nChainWork = i ? blocks[i - 1].nChainWork + GetBlockProof(blocks[i - 1]) : arith_uint256(0);
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}
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// Result should be the same as if last difficulty was used
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arith_uint256 bnAvg;
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bnAvg.SetCompact(blocks[lastBlk].nBits);
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EXPECT_EQ(CalculateNextWorkRequired(bnAvg,
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blocks[lastBlk].GetMedianTimePast(),
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blocks[firstBlk].GetMedianTimePast(),
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params),
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GetNextWorkRequired(&blocks[lastBlk], nullptr, params));
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// Result should be unchanged, modulo integer division precision loss
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arith_uint256 bnRes;
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bnRes.SetCompact(0x1e7fffff);
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bnRes /= params.AveragingWindowTimespan();
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bnRes *= params.AveragingWindowTimespan();
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EXPECT_EQ(bnRes.GetCompact(), GetNextWorkRequired(&blocks[lastBlk], nullptr, params));
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// Randomise the final block time (plus 1 to ensure it is always different)
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blocks[lastBlk].nTime += GetRand(params.nPowTargetSpacing/2) + 1;
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// Result should be the same as if last difficulty was used
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bnAvg.SetCompact(blocks[lastBlk].nBits);
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EXPECT_EQ(CalculateNextWorkRequired(bnAvg,
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blocks[lastBlk].GetMedianTimePast(),
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blocks[firstBlk].GetMedianTimePast(),
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params),
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GetNextWorkRequired(&blocks[lastBlk], nullptr, params));
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// Result should not be unchanged
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EXPECT_NE(0x1e7fffff, GetNextWorkRequired(&blocks[lastBlk], nullptr, params));
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// Change the final block difficulty
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blocks[lastBlk].nBits = 0x1e0fffff;
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// Result should not be the same as if last difficulty was used
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bnAvg.SetCompact(blocks[lastBlk].nBits);
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EXPECT_NE(CalculateNextWorkRequired(bnAvg,
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blocks[lastBlk].GetMedianTimePast(),
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blocks[firstBlk].GetMedianTimePast(),
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params),
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GetNextWorkRequired(&blocks[lastBlk], nullptr, params));
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// Result should be the same as if the average difficulty was used
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arith_uint256 average = UintToArith256(uint256S("0000796968696969696969696969696969696969696969696969696969696969"));
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EXPECT_EQ(CalculateNextWorkRequired(average,
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blocks[lastBlk].GetMedianTimePast(),
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blocks[firstBlk].GetMedianTimePast(),
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params),
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GetNextWorkRequired(&blocks[lastBlk], nullptr, params));
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}
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