def testChiefAsLeader(self):
    cluster_spec = {
        "chief": ["127.0.0.1:1234"],
        "worker": ["127.0.0.1:8964", "127.0.0.1:2333"],
        "ps": ["127.0.0.1:1926", "127.0.0.1:3141"]
    }
    self.assertEqual(
        multi_worker_util.collective_leader(cluster_spec, "worker", 0),
        "/job:chief/replica:0/task:0")