Method MakeBuffered

cpp/src/arrow/io/buffered_test.cc:928–951

class TestBufferedInputStreamRandom : public ::testing::Test {
 public:
  void MakeBuffered(int64_t data_size, int64_t buffer_size,
                    std::optional<int64_t> read_bound = std::nullopt) {
    buffer_size_ = buffer_size;
    data_.clear();
    data_.reserve(data_size);
    while (data_.size() < static_cast<size_t>(data_size)) {
      data_.append(kExample1, /*pos*/ 0,
                   /*count*/ static_cast<size_t>(data_size) - data_.size());
    }
    EXPECT_EQ(data_.size(), data_size);

    // Clear dependent streams in reverse order
    buffered_.reset();
    tracked_.reset();
    // Read from a copy of data, so that data_.substr() below doesn't invalidate it
    raw_ = BufferReader::FromString(data_);
    tracked_ = TrackedRandomAccessFile::Make(raw_.get());
    EXPECT_OK_AND_ASSIGN(buffered_,
                         BufferedInputStream::Create(buffer_size, default_memory_pool(),
                                                     tracked_, read_bound.value_or(-1)));
    if (read_bound) {
      data_ = data_.substr(0, *read_bound);
    }
  }

  void TestReads() {
    std::default_random_engine gen(/*seed*/ 42);