code: def test_execute_complete_success(self, mock_log):
      expected_event_message = "Event message (success)"
      event = {
          "status": "success",
          "message": expected_event_message,
      }
      operator = S3ToGCSOperator(task_id=TASK_ID, bucket=S3_BUCKET)
      operator.execute_complete(context=mock.MagicMock(), event=event)
  
      mock_log.return_value.info.assert_called_once_with(
          "%s completed with response %s ", TASK_ID, event["message"]
      )
  
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 6 for calling the TestS3ToGoogleCloudStorageOperatorDeferrable obj's underlying member method code with example usage: obj.test_execute_complete_success(mock_log) without return types