As discussed in  https://github.com/apache/airflow/pull/15534#discussion_r620500075, we could possibly rewrite Beam Hook to remove the need of storing state in it.
mock_list = (
            self.mock_dataflow
            .projects.return_value
            .locations.return_value
            .jobs.return_value
            .messages.return_value
            .list
        )
        mock_list_next = (
            self.mock_dataflow.
            projects.return_value.
            locations.return_value.
            jobs.return_value
            .messages.return_value
            .list_next
        )
        
        mock_list.return_value.execute.return_value = "response_1"
        mock_list_next.return_value = None
        jobs_controller = _DataflowJobsController(
            dataflow=self.mock_dataflow,
            project_number=TEST_PROJECT,