if (!status.ok())
    GTEST_SKIP() << "NewWritableFile() not supported: " << status;

  const std::string test_data("asdf");
  status = new_file->Append(test_data);
  if (!status.ok()) GTEST_SKIP() << "Append() not supported: " << status;
  status = new_file->Flush();
  if (!status.ok()) GTEST_SKIP() << "Flush() not supported: " << status;
  status = new_file->Close();

  *result = filename_;
  return OkStatus();
}

Status ModularWritableFile::Append(StringPiece data) {
  if (ops_->append == nullptr)
    return errors::Unimplemented(tensorflow::strings::StrCat(
        "Append() not implemented for ", filename_));

  UniquePtrTo_TF_Status plugin_status(TF_NewStatus(), TF_DeleteStatus);
  ops_->append(file_.get(), data.data(), data.size(), plugin_status.get());

_current_module = _sys.modules[__name__]
_tf_api_dir = _os.path.dirname(_os.path.dirname(_API_MODULE.__file__))
if not hasattr(_current_module, "__path__"):
  __path__ = [_tf_api_dir]
elif _tf_api_dir not in __path__:
  __path__.append(_tf_api_dir)

# Hook external TensorFlow modules.
# Import compat before trying to import summary from tensorboard, so that
# reexport_tf_summary can get compat from sys.modules. Only needed if using
# lazy loading.

                    << TF_Message(s);

    const char* data = "Hello, world!\n";
    TF_AppendWritableFile(handle, data, strlen(data), s);
    ASSERT_TF_OK(s) << "TF_AppendWritableFile failed to append data to file at "
                    << filepath << ": " << TF_Message(s);

    TF_CloseWritableFile(handle, s);
    ASSERT_TF_OK(s) << "TF_CloseWritableFile failed to close handle to "

_tf_api_dir = _os.path.dirname(_os.path.dirname(_API_MODULE.__file__))
_current_module = _sys.modules[__name__]

if not hasattr(_current_module, "__path__"):
  __path__ = [_tf_api_dir]
elif _tf_api_dir not in __path__:
  __path__.append(_tf_api_dir)

# Hook external TensorFlow modules.

# Load tensorflow-io-gcs-filesystem if enabled
if (_os.getenv("TF_USE_MODULAR_FILESYSTEM", "0") == "true" or
    _os.getenv("TF_USE_MODULAR_FILESYSTEM", "0") == "1"):

GCSFile::GCSFile(google::cloud::storage::Client&& gcs_client)
    : gcs_client(gcs_client), block_cache_lock() {
  const char* append_mode = std::getenv(kAppendMode);
  compose = (append_mode != nullptr) && (!strcmp(kAppendMode, append_mode));

  uint64_t value;
  block_size = kDefaultBlockSize;
  size_t max_bytes = kDefaultMaxCacheSize;
  uint64_t max_staleness = kDefaultMaxStaleness;

// Return the number of outputs in the list.
int TF_OutputListNumOutputs(TF_OutputList* o);
// Return the `i`th output in the list.
TF_AbstractTensor* TF_OutputListGet(TF_OutputList* o, int i);
// Append a tensor at the end of the output list, growing its size by one.
void TF_OutputListPushBack(TF_OutputList* o, TF_AbstractTensor* tensor,
                           TF_Status*);

  auto* cc_file = reinterpret_cast<::tensorflow::WritableFile*>(handle);
  TF_SetStatus(status, TF_OK, "");
  ::tensorflow::Set_TF_Status_from_Status(
      status, cc_file->Append(::tensorflow::StringPiece{data, length}));
}

void TF_DeleteFile(const char* filename, TF_Status* status) {
  TF_SetStatus(status, TF_OK, "");
  ::tensorflow::Set_TF_Status_from_Status(

#endif  // !defined(PLATFORM_WINDOWS)
}

void DefineFunction(const char* name, TF_Function** func,
                    const char* description = nullptr,
                    bool append_hash = false) {
  std::unique_ptr<TF_Graph, decltype(&TF_DeleteGraph)> func_graph(
      TF_NewGraph(), TF_DeleteGraph);
  std::unique_ptr<TF_Status, decltype(&TF_DeleteStatus)> s(TF_NewStatus(),

                 /*append_hash=*/false);
  tensorflow::FunctionDef fdef;
  ASSERT_TRUE(GetFunctionDef(func_, &fdef));
  ASSERT_EQ(string("long_func_name"), fdef.signature().name());
}

TEST_F(CApiFunctionTest, AppendHash) {
  DefineFunction("func_name_base", &func_, "Return something",
                 /*append_hash=*/true);
  tensorflow::FunctionDef fdef;