def testUnexpectedInput(self):
    cluster_spec = ["127.0.0.1:8964", "127.0.0.1:2333"]

    with self.assertRaisesRegex(
        ValueError,
        "`cluster_spec' should be dict or a `tf.train.ClusterSpec` or a "
        "`tf.train.ClusterDef` object"):
      multi_worker_util.normalize_cluster_spec(cluster_spec)