Function TinyintArrayFromJSON

cpp/src/arrow/compute/kernels/scalar_cast_test.cc:4453–4458

}

std::shared_ptr<Array> TinyintArrayFromJSON(const std::string& json_data) {
  auto arr = ArrayFromJSON(int8(), json_data);
  auto ext_data = arr->data()->Copy();
  ext_data->type = tinyint();
  return MakeArray(ext_data);
}

TEST(Cast, ExtensionTypeToIntDowncast) {
  auto smallint = std::make_shared<SmallintType>();