code: def test_transfer_files_async_error_no_files(self):
      operator = S3ToGCSOperator(
          task_id=TASK_ID,
          bucket=S3_BUCKET,
          prefix=S3_PREFIX,
          delimiter=S3_DELIMITER,
          gcp_conn_id=GCS_CONN_ID,
          dest_gcs=GCS_PATH_PREFIX,
      )
      expected_error_message = (
          "List of transferring files cannot be empty"
      )
      with pytest.raises(ValueError, match=expected_error_message):
          operator.transfer_files_async(
              files=[],
              gcs_hook=mock.MagicMock(),
              s3_hook=mock.MagicMock(),
          )
  
imports: from __future__ import annotations
  from unittest import mock
  from unittest.mock import PropertyMock
  import pytest
  import time_machine
  from airflow.exceptions import AirflowException, TaskDeferred
  from airflow.providers.google.cloud.hooks.cloud_storage_transfer_service import CloudDataTransferServiceHook
  from airflow.providers.google.cloud.transfers.s3_to_gcs import S3ToGCSOperator
  from airflow.utils.timezone import utcnow
label_desc: Use image node_id 4 for calling the TestS3ToGoogleCloudStorageOperatorDeferrable obj's underlying member method code with example usage: obj.test_transfer_files_async_error_no_files() without return types