def METHOD_NAME(cluster, sentinel, master_ip):
    # Put first sentinel 'foo' down
    cluster.nodes_timeout.add(("foo", 26379))
    address = sentinel.discover_master("mymaster")
    assert address == (master_ip, 6379)
    # 'bar' is now first sentinel
    assert sentinel.sentinels[0].id == ("bar", 26379)