'Ensure cluster.metadata.get_replicas return correctly when not attached to keyspace'

@local
def test_replicas(self):

    if (murmur3 is None):
        raise unittest.SkipTest('the    murmur3    extension    is    not    available')
    cluster = Cluster(protocol_version=PROTOCOL_VERSION)
    self.assertEqual(cluster.metadata.get_replicas('test3rf', 'key'), [])
    cluster.connect('test3rf')
    self.assertNotEqual(list(cluster.metadata.get_replicas('test3rf', six.b('key'))), [])
    host = list(cluster.metadata.get_replicas('test3rf', six.b('key')))[0]
    self.assertEqual(host.datacenter, 'dc1')
    self.assertEqual(host.rack, 'r1')
    cluster.shutdown()
