text: // Copyright (c) 2020 The TNGC Core developers
  // Distributed under the MIT software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #include <primitives/block.h>
  #include <test/fuzz/FuzzedDataProvider.h>
  #include <test/fuzz/fuzz.h>
  #include <test/fuzz/util.h>
  #include <uint256.h>
  
  #include <cassert>
  #include <cstdint>
  #include <optional>
  #include <string>
  #include <vector>
  
  void test_one_input(const std::vector<uint8_t>& buffer)
  {
      FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
      const std::optional<CBlockHeader> block_header = ConsumeDeserializable<CBlockHeader>(fuzzed_data_provider);
      if (!block_header) {
          return;
      }
      {
          const uint256 hash = block_header->GetHash();
          static const uint256 u256_max(uint256S("ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"));
          assert(hash != u256_max);
          assert(block_header->GetBlockTime() == block_header->nTime);
          assert(block_header->IsNull() == (block_header->nBits == 0));
      }
      {
          CBlockHeader mut_block_header = *block_header;
          mut_block_header.SetNull();
          assert(mut_block_header.IsNull());
          CBlock block{*block_header};
          assert(block.GetBlockHeader().GetHash() == block_header->GetHash());
          (void)block.ToString();
          block.SetNull();
          assert(block.GetBlockHeader().GetHash() == mut_block_header.GetHash());
      }
      {
          std::optional<CBlockLocator> block_locator = ConsumeDeserializable<CBlockLocator>(fuzzed_data_provider);
          if (block_locator) {
              (void)block_locator->IsNull();
              block_locator->SetNull();
              assert(block_locator->IsNull());
          }
      }
  }
  