Method expected_rows

cpp/src/arrow/dataset/test_util_internal.h:677–677

 public:
  int64_t expected_batches() const { return GetParam().num_batches; }
  int64_t expected_rows() const { return GetParam().expected_rows(); }

  std::shared_ptr<RecordBatchReader> GetRecordBatchReader(
      std::shared_ptr<Schema> schema) override {