def test_create_transfer_manager_with_default_config(self):
        """Ensure we still default to classic transfer manager when CRT
        is disabled.
        """
        with mock.patch('boto3.s3.transfer.HAS_CRT', False):
            client = create_mock_client()
            config = TransferConfig()
            assert config.preferred_transfer_client == "auto"
            with mock.patch('boto3.s3.transfer.TransferManager') as manager:
                create_transfer_manager(client, config)
                assert manager.call_args == mock.call(
                    client, config, None, None
                )
Ensure we still default to classic transfer manager when CRT
        is disabled.
        
tests/unit/s3/test_transfer.py