Method TestCacheMetadata

cpp/src/arrow/dataset/scanner_test.cc:1000–1031

  }

  void TestCacheMetadata(std::function<Status(Scanner*)> consume_scanner) {
    // Test that ClearCachedMetadata() is called if ScanOptions::cache_metadata is false.
    SetSchema({field("i32", int32())});
    auto batch = ConstantArrayGenerator::Zeroes(GetParam().items_per_batch, schema_);
    RecordBatchVector batches{batch, batch};
    auto frag1 = std::make_shared<ClearCachedMetadataFragment>(batches);
    auto frag2 = std::make_shared<ClearCachedMetadataFragment>(batches);
    auto check_metadata_clear_counts = [&](const std::vector<int>& expected) {
      auto actual =
          std::vector<int>{frag1->metadata_clear_count(), frag2->metadata_clear_count()};
      ASSERT_EQ(expected, actual);
    };
    {
      ScannerBuilder builder(
          std::make_shared<FragmentDataset>(schema_, FragmentVector{frag1, frag2}),
          options_);
      ASSERT_OK(builder.UseThreads(GetParam().use_threads));
      ASSERT_OK_AND_ASSIGN(auto scanner, builder.Finish());
      ASSERT_OK(consume_scanner(scanner.get()));
      check_metadata_clear_counts({0, 0});
    }
    options_->cache_metadata = false;
    {
      ScannerBuilder builder(
          std::make_shared<FragmentDataset>(schema_, FragmentVector{frag1, frag2}),
          options_);
      ASSERT_OK(builder.UseThreads(GetParam().use_threads));
      ASSERT_OK_AND_ASSIGN(auto scanner, builder.Finish());
      ASSERT_OK(consume_scanner(scanner.get()));
      check_metadata_clear_counts({1, 1});
    }
  }
};

TEST_P(TestScanner, Scan) {