text: // Copyright (c) 2018 The SalemCash developers
  // Distributed under the MIT software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #include <chain.h>
  #include <util.h>
  #include <test/test_salemcash.h>
  
  #include <vector>
  
  #include <boost/test/unit_test.hpp>
  
  #define SKIPLIST_LENGTH 300000
  
  BOOST_FIXTURE_TEST_SUITE(skiplist_tests, BasicTestingSetup)
  
  BOOST_AUTO_TEST_CASE(skiplist_test)
  {
      std::vector<CBlockIndex> vIndex(SKIPLIST_LENGTH);
  
      for (int i=0; i<SKIPLIST_LENGTH; i++) {
          vIndex[i].nHeight = i;
          vIndex[i].pprev = (i == 0) ? nullptr : &vIndex[i - 1];
          vIndex[i].BuildSkip();
      }
  
      for (int i=0; i<SKIPLIST_LENGTH; i++) {
          if (i > 0) {
              BOOST_CHECK(vIndex[i].pskip == &vIndex[vIndex[i].pskip->nHeight]);
              BOOST_CHECK(vIndex[i].pskip->nHeight < i);
          } else {
              BOOST_CHECK(vIndex[i].pskip == nullptr);
          }
      }
  
      for (int i=0; i < 1000; i++) {
          int from = InsecureRandRange(SKIPLIST_LENGTH - 1);
          int to = InsecureRandRange(from + 1);
  
          BOOST_CHECK(vIndex[SKIPLIST_LENGTH - 1].GetAncestor(from) == &vIndex[from]);
          BOOST_CHECK(vIndex[from].GetAncestor(to) == &vIndex[to]);
          BOOST_CHECK(vIndex[from].GetAncestor(0) == vIndex.data());
      }
  }
  
  BOOST_AUTO_TEST_CASE(getlocator_test)
  {
      // Build a main chain 100000 blocks long.
      std::vector<uint256> vHashMain(100000);
      std::vector<CBlockIndex> vBlocksMain(100000);
      for (unsigned int i=0; i<vBlocksMain.size(); i++) {
          vHashMain[i] = ArithToUint256(i); // Set the hash equal to the height, so we can quickly check the distances.
          vBlocksMain[i].nHeight = i;
          vBlocksMain[i].pprev = i ? &vBlocksMain[i - 1] : nullptr;
          vBlocksMain[i].phashBlock = &vHashMain[i];
          vBlocksMain[i].BuildSkip();
          BOOST_CHECK_EQUAL((int)UintToArith256(vBlocksMain[i].GetBlockHash()).GetLow64(), vBlocksMain[i].nHeight);
          BOOST_CHECK(vBlocksMain[i].pprev == nullptr || vBlocksMain[i].nHeight == vBlocksMain[i].pprev->nHeight + 1);
      }
  
      // Build a branch that splits off at block 49999, 50000 blocks long.
      std::vector<uint256> vHashSide(50000);
      std::vector<CBlockIndex> vBlocksSide(50000);
      for (unsigned int i=0; i<vBlocksSide.size(); i++) {
          vHashSide[i] = ArithToUint256(i + 50000 + (arith_uint256(1) << 128)); // Add 1<<128 to the hashes, so GetLow64() still returns the height.
          vBlocksSide[i].nHeight = i + 50000;
          vBlocksSide[i].pprev = i ? &vBlocksSide[i - 1] : (vBlocksMain.data()+49999);
          vBlocksSide[i].phashBlock = &vHashSide[i];
          vBlocksSide[i].BuildSkip();
          BOOST_CHECK_EQUAL((int)UintToArith256(vBlocksSide[i].GetBlockHash()).GetLow64(), vBlocksSide[i].nHeight);
          BOOST_CHECK(vBlocksSide[i].pprev == nullptr || vBlocksSide[i].nHeight == vBlocksSide[i].pprev->nHeight + 1);
      }
  
      // Build a CChain for the main branch.
      CChain chain;
      chain.SetTip(&vBlocksMain.back());
  
      // Test 100 random starting points for locators.
      for (int n=0; n<100; n++) {
          int r = InsecureRandRange(150000);
          CBlockIndex* tip = (r < 100000) ? &vBlocksMain[r] : &vBlocksSide[r - 100000];
          CBlockLocator locator = chain.GetLocator(tip);
  
          // The first result must be the block itself, the last one must be genesis.
          BOOST_CHECK(locator.vHave.front() == tip->GetBlockHash());
          BOOST_CHECK(locator.vHave.back() == vBlocksMain[0].GetBlockHash());
  
          // Entries 1 through 11 (inclusive) go back one step each.
          for (unsigned int i = 1; i < 12 && i < locator.vHave.size() - 1; i++) {
              BOOST_CHECK_EQUAL(UintToArith256(locator.vHave[i]).GetLow64(), tip->nHeight - i);
          }
  
          // The further ones (excluding the last one) go back with exponential steps.
          unsigned int dist = 2;
          for (unsigned int i = 12; i < locator.vHave.size() - 1; i++) {
              BOOST_CHECK_EQUAL(UintToArith256(locator.vHave[i - 1]).GetLow64() - UintToArith256(locator.vHave[i]).GetLow64(), dist);
              dist *= 2;
          }
      }
  }
  
  BOOST_AUTO_TEST_CASE(findearliestatleast_test)
  {
      std::vector<uint256> vHashMain(100000);
      std::vector<CBlockIndex> vBlocksMain(100000);
      for (unsigned int i=0; i<vBlocksMain.size(); i++) {
          vHashMain[i] = ArithToUint256(i); // Set the hash equal to the height
          vBlocksMain[i].nHeight = i;
          vBlocksMain[i].pprev = i ? &vBlocksMain[i - 1] : nullptr;
          vBlocksMain[i].phashBlock = &vHashMain[i];
          vBlocksMain[i].BuildSkip();
          if (i < 10) {
              vBlocksMain[i].nTime = i;
              vBlocksMain[i].nTimeMax = i;
          } else {
              // randomly choose something in the range [MTP, MTP*2]
              int64_t medianTimePast = vBlocksMain[i].GetMedianTimePast();
              int r = InsecureRandRange(medianTimePast);
              vBlocksMain[i].nTime = r + medianTimePast;
              vBlocksMain[i].nTimeMax = std::max(vBlocksMain[i].nTime, vBlocksMain[i-1].nTimeMax);
          }
      }
      // Check that we set nTimeMax up correctly.
      unsigned int curTimeMax = 0;
      for (unsigned int i=0; i<vBlocksMain.size(); ++i) {
          curTimeMax = std::max(curTimeMax, vBlocksMain[i].nTime);
          BOOST_CHECK(curTimeMax == vBlocksMain[i].nTimeMax);
      }
  
      // Build a CChain for the main branch.
      CChain chain;
      chain.SetTip(&vBlocksMain.back());
  
      // Verify that FindEarliestAtLeast is correct.
      for (unsigned int i=0; i<10000; ++i) {
          // Pick a random element in vBlocksMain.
          int r = InsecureRandRange(vBlocksMain.size());
          int64_t test_time = vBlocksMain[r].nTime;
          CBlockIndex *ret = chain.FindEarliestAtLeast(test_time);
          BOOST_CHECK(ret->nTimeMax >= test_time);
          BOOST_CHECK((ret->pprev==nullptr) || ret->pprev->nTimeMax < test_time);
          BOOST_CHECK(vBlocksMain[r].GetAncestor(ret->nHeight) == ret);
      }
  }
  
  BOOST_AUTO_TEST_CASE(findearliestatleast_edge_test)
  {
      std::list<CBlockIndex> blocks;
      for (unsigned int timeMax : {100, 100, 100, 200, 200, 200, 300, 300, 300}) {
          CBlockIndex* prev = blocks.empty() ? nullptr : &blocks.back();
          blocks.emplace_back();
          blocks.back().nHeight = prev ? prev->nHeight + 1 : 0;
          blocks.back().pprev = prev;
          blocks.back().BuildSkip();
          blocks.back().nTimeMax = timeMax;
      }
  
      CChain chain;
      chain.SetTip(&blocks.back());
  
      BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(50)->nHeight, 0);
      BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(100)->nHeight, 0);
      BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(150)->nHeight, 3);
      BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(200)->nHeight, 3);
      BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(250)->nHeight, 6);
      BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(300)->nHeight, 6);
      BOOST_CHECK(!chain.FindEarliestAtLeast(350));
  
      BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(0)->nHeight, 0);
      BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(-1)->nHeight, 0);
  
      BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(std::numeric_limits<int64_t>::min())->nHeight, 0);
      BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(std::numeric_limits<unsigned int>::min())->nHeight, 0);
      BOOST_CHECK_EQUAL(chain.FindEarliestAtLeast(-int64_t(std::numeric_limits<unsigned int>::max()) - 1)->nHeight, 0);
      BOOST_CHECK(!chain.FindEarliestAtLeast(std::numeric_limits<int64_t>::max()));
      BOOST_CHECK(!chain.FindEarliestAtLeast(std::numeric_limits<unsigned int>::max()));
      BOOST_CHECK(!chain.FindEarliestAtLeast(int64_t(std::numeric_limits<unsigned int>::max()) + 1));
  }
  
  BOOST_AUTO_TEST_SUITE_END()
  