def METHOD_NAME(self) -> None:
    accumulated_results = job_run_result.JobRunResult.accumulate([
        job_run_result.JobRunResult(stdout='', stderr='a' * 1999),
        job_run_result.JobRunResult(stdout='', stderr='b' * 3000),
    ])
    self.assertEqual(len(accumulated_results), 1)
    self.assertItemsEqual(
        accumulated_results[0].stderr.split('\n'), ['a' * 1999, 'b' * 3000])