test_policies.py 文件源码

def test_wrap_round_robin(self):
        cluster = Mock(spec=Cluster)
        cluster.metadata = Mock(spec=Metadata)
        hosts = [Host(str(i), SimpleConvictionPolicy) for i in range(4)]
        for host in hosts:
            host.set_up()

        def get_replicas(keyspace, packed_key):
            index = struct.unpack('>i', packed_key)[0]
            return list(islice(cycle(hosts), index, index + 2))

        cluster.metadata.get_replicas.side_effect = get_replicas

        policy = TokenAwarePolicy(RoundRobinPolicy())
        policy.populate(cluster, hosts)

        for i in range(4):
            query = Statement(routing_key=struct.pack('>i', i), keyspace='keyspace_name')
            qplan = list(policy.make_query_plan(None, query))

            replicas = get_replicas(None, struct.pack('>i', i))
            other = set(h for h in hosts if h not in replicas)
            self.assertEqual(replicas, qplan[:2])
            self.assertEqual(other, set(qplan[2:]))

        # Should use the secondary policy
        for i in range(4):
            qplan = list(policy.make_query_plan())

            self.assertEqual(set(qplan), set(hosts))