Merge "cow_api_test: big replace op" into main

    ASSERT_EQ(sink, data);

}

TEST_F(CowTestV3, BigReplaceOp) {

    CowOptions options;

    options.op_count_max = 10000;

    options.batch_write = true;

    options.cluster_ops = 2048;

    auto writer = CreateCowWriter(3, options, GetCowFd());

    std::string data = "This is some data, believe it";

    data.resize(options.block_size * 4096, '\0');

    for (int i = 0; i < data.size(); i++) {

        data[i] = static_cast<char>('A' + i / options.block_size);

    }

    ASSERT_TRUE(writer->AddRawBlocks(5, data.data(), data.size()));

    ASSERT_TRUE(writer->Finalize());

    CowReader reader;

    ASSERT_TRUE(reader.Parse(cow_->fd));

    const auto& header = reader.header_v3();

    ASSERT_EQ(header.op_count, 4096);

    auto iter = reader.GetOpIter();

    ASSERT_NE(iter, nullptr);

    ASSERT_FALSE(iter->AtEnd());

    size_t i = 0;

    while (!iter->AtEnd()) {

        auto op = iter->Get();

        std::string sink(options.block_size, '\0');

        ASSERT_EQ(op->type(), kCowReplaceOp);

        ASSERT_EQ(op->data_length, options.block_size);

        ASSERT_EQ(op->new_block, 5 + i);

        ASSERT_TRUE(ReadData(reader, op, sink.data(), options.block_size));

        ASSERT_EQ(std::string_view(sink),

                  std::string_view(data).substr(i * options.block_size, options.block_size))

                << " readback data for " << i << "th block does not match";

        iter->Next();

        i++;

    }

}

TEST_F(CowTestV3, ConsecutiveReplaceOp) {

    CowOptions options;

    options.op_count_max = 20;