text: // 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 "pow.h"
  #include "random.h"
  #include "util.h"
  #include "test/test_desire.h"
  
  #include <boost/test/unit_test.hpp>
  
  using namespace std;
  
  BOOST_FIXTURE_TEST_SUITE(pow_tests, BasicTestingSetup)
  
  /* Test calculation of next difficulty target with DGW */
  BOOST_AUTO_TEST_CASE(get_next_work)
  {
      SelectParams(CBaseChainParams::MAIN);
      const Consensus::Params& params = Params().GetConsensus();
  
      // build the chain of 24 blocks
      CBlockIndex blockIndexLast;
      blockIndexLast.nHeight = 123456;
      blockIndexLast.nTime = 1408732489;
      blockIndexLast.nBits = 0x1b1418d4;
      CBlockIndex blockIndexPrev1 = CBlockIndex();
      blockIndexPrev1.nTime = 1408732257;  // Block #123455
      blockIndexPrev1.nBits = 0x1b13b83f;
      blockIndexLast.pprev = &blockIndexPrev1;
      CBlockIndex blockIndexPrev2 = CBlockIndex();
      blockIndexPrev2.nTime = 1408732229;  // Block #123454
      blockIndexPrev2.nBits = 0x1b10460b;
      blockIndexPrev1.pprev = &blockIndexPrev2;
      CBlockIndex blockIndexPrev3 = CBlockIndex();
      blockIndexPrev3.nTime = 1408731256;  // Block #123453
      blockIndexPrev3.nBits = 0x1b113ff1;
      blockIndexPrev2.pprev = &blockIndexPrev3;
      CBlockIndex blockIndexPrev4 = CBlockIndex();
      blockIndexPrev4.nTime = 1408731242;  // Block #123452
      blockIndexPrev4.nBits = 0x1b0fed89;
      blockIndexPrev3.pprev = &blockIndexPrev4;
      CBlockIndex blockIndexPrev5 = CBlockIndex();
      blockIndexPrev5.nTime = 1408730914;  // Block #123451
      blockIndexPrev5.nBits = 0x1b10b864;
      blockIndexPrev4.pprev = &blockIndexPrev5;
      CBlockIndex blockIndexPrev6 = CBlockIndex();
      blockIndexPrev6.nTime = 1408730862;  // Block #123450
      blockIndexPrev6.nBits = 0x1b0dd168;
      blockIndexPrev5.pprev = &blockIndexPrev6;
      CBlockIndex blockIndexPrev7 = CBlockIndex();
      blockIndexPrev7.nTime = 1408730179;  // Block #123449
      blockIndexPrev7.nBits = 0x1b0c03d6;
      blockIndexPrev6.pprev = &blockIndexPrev7;
      CBlockIndex blockIndexPrev8 = CBlockIndex();
      blockIndexPrev8.nTime = 1408729678;  // Block #123448
      blockIndexPrev8.nBits = 0x1b0c9ab8;
      blockIndexPrev7.pprev = &blockIndexPrev8;
      CBlockIndex blockIndexPrev9 = CBlockIndex();
      blockIndexPrev9.nTime = 1408729647;  // Block #123447
      blockIndexPrev9.nBits = 0x1b0dfaff;
      blockIndexPrev8.pprev = &blockIndexPrev9;
      CBlockIndex blockIndexPrev10 = CBlockIndex();
      blockIndexPrev10.nTime = 1408729587;  // Block #123446
      blockIndexPrev10.nBits = 0x1b10e878;
      blockIndexPrev9.pprev = &blockIndexPrev10;
      CBlockIndex blockIndexPrev11 = CBlockIndex();
      blockIndexPrev11.nTime = 1408729576;  // Block #123445
      blockIndexPrev11.nBits = 0x1b1063d0;
      blockIndexPrev10.pprev = &blockIndexPrev11;
      CBlockIndex blockIndexPrev12 = CBlockIndex();
      blockIndexPrev12.nTime = 1408729474;  // Block #123444
      blockIndexPrev12.nBits = 0x1b104297;
      blockIndexPrev11.pprev = &blockIndexPrev12;
      CBlockIndex blockIndexPrev13 = CBlockIndex();
      blockIndexPrev13.nTime = 1408729305;  // Block #123443
      blockIndexPrev13.nBits = 0x1b107556;
      blockIndexPrev12.pprev = &blockIndexPrev13;
      CBlockIndex blockIndexPrev14 = CBlockIndex();
      blockIndexPrev14.nTime = 1408729179;  // Block #123442
      blockIndexPrev14.nBits = 0x1b110764;
      blockIndexPrev13.pprev = &blockIndexPrev14;
      CBlockIndex blockIndexPrev15 = CBlockIndex();
      blockIndexPrev15.nTime = 1408729116;  // Block #123441
      blockIndexPrev15.nBits = 0x1b1141bf;
      blockIndexPrev14.pprev = &blockIndexPrev15;
      CBlockIndex blockIndexPrev16 = CBlockIndex();
      blockIndexPrev16.nTime = 1408728950;  // Block #123440
      blockIndexPrev16.nBits = 0x1b1123f9;
      blockIndexPrev15.pprev = &blockIndexPrev16;
      CBlockIndex blockIndexPrev17 = CBlockIndex();
      blockIndexPrev17.nTime = 1408728756;  // Block #123439
      blockIndexPrev17.nBits = 0x1b118d9c;
      blockIndexPrev16.pprev = &blockIndexPrev17;
      CBlockIndex blockIndexPrev18 = CBlockIndex();
      blockIndexPrev18.nTime = 1408728744;  // Block #123438
      blockIndexPrev18.nBits = 0x1b11abac;
      blockIndexPrev17.pprev = &blockIndexPrev18;
      CBlockIndex blockIndexPrev19 = CBlockIndex();
      blockIndexPrev19.nTime = 1408728608;  // Block #123437
      blockIndexPrev19.nBits = 0x1b11951e;
      blockIndexPrev18.pprev = &blockIndexPrev19;
      CBlockIndex blockIndexPrev20 = CBlockIndex();
      blockIndexPrev20.nTime = 1408728495;  // Block #123436
      blockIndexPrev20.nBits = 0x1b121cf3;
      blockIndexPrev19.pprev = &blockIndexPrev20;
      CBlockIndex blockIndexPrev21 = CBlockIndex();
      blockIndexPrev21.nTime = 1408728479;  // Block #123435
      blockIndexPrev21.nBits = 0x1b11a33c;
      blockIndexPrev20.pprev = &blockIndexPrev21;
      CBlockIndex blockIndexPrev22 = CBlockIndex();
      blockIndexPrev22.nTime = 1408728332;  // Block #123434
      blockIndexPrev22.nBits = 0x1b10e09e;
      blockIndexPrev21.pprev = &blockIndexPrev22;
      CBlockIndex blockIndexPrev23 = CBlockIndex();
      blockIndexPrev23.nTime = 1408728124;  // Block #123433
      blockIndexPrev23.nBits = 0x1b104be1;
      blockIndexPrev22.pprev = &blockIndexPrev23;
  
      CBlockHeader blockHeader;
      blockHeader.nTime = 1408732505; // Block #123457
      BOOST_CHECK_EQUAL(GetNextWorkRequired(&blockIndexLast, &blockHeader, params), 0x1b1441de); // Block #123457 has 0x1b1441de
  }
  
  /* Test the constraint on the upper bound for next work */
  // BOOST_AUTO_TEST_CASE(get_next_work_pow_limit)
  // {
  //     SelectParams(CBaseChainParams::MAIN);
  //     const Consensus::Params& params = Params().GetConsensus();
  
  //     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, params), 0x1d00ffff);
  // }
  
  /* Test the constraint on the lower bound for actual time taken */
  // BOOST_AUTO_TEST_CASE(get_next_work_lower_limit_actual)
  // {
  //     SelectParams(CBaseChainParams::MAIN);
  //     const Consensus::Params& params = Params().GetConsensus();
  
  //     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, params), 0x1c0168fd);
  // }
  
  /* Test the constraint on the upper bound for actual time taken */
  // BOOST_AUTO_TEST_CASE(get_next_work_upper_limit_actual)
  // {
  //     SelectParams(CBaseChainParams::MAIN);
  //     const Consensus::Params& params = Params().GetConsensus();
  
  //     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, params), 0x1d00e1fd);
  // }
  
  BOOST_AUTO_TEST_CASE(GetBlockProofEquivalentTime_test)
  {
      SelectParams(CBaseChainParams::MAIN);
      const Consensus::Params& params = Params().GetConsensus();
  
      std::vector<CBlockIndex> blocks(10000);
      for (int i = 0; i < 10000; i++) {
          blocks[i].pprev = i ? &blocks[i - 1] : NULL;
          blocks[i].nHeight = i;
          blocks[i].nTime = 1269211443 + i * params.nPowTargetSpacing;
          blocks[i].nBits = 0x207fffff; /* target 0x7fffff000... */
          blocks[i].nChainWork = i ? blocks[i - 1].nChainWork + GetBlockProof(blocks[i - 1]) : arith_uint256(0);
      }
  
      for (int j = 0; j < 1000; j++) {
          CBlockIndex *p1 = &blocks[GetRand(10000)];
          CBlockIndex *p2 = &blocks[GetRand(10000)];
          CBlockIndex *p3 = &blocks[GetRand(10000)];
  
          int64_t tdiff = GetBlockProofEquivalentTime(*p1, *p2, *p3, params);
          BOOST_CHECK_EQUAL(tdiff, p1->GetBlockTime() - p2->GetBlockTime());
      }
  }
  
  BOOST_AUTO_TEST_SUITE_END()
  