boolean isCheckpointTopic(String topic) {
        return replicationPolicy.isCheckpointsTopic(topic);
    }
@Test
    public void testIsCheckpointTopic() {
        MirrorClient client = new FakeMirrorClient();
        assertTrue(client.isCheckpointTopic("source1.checkpoints.internal"));
        assertFalse(client.isCheckpointTopic("checkpoints.internal"));
        assertFalse(client.isCheckpointTopic("checkpoints-internal"));
        assertFalse(client.isCheckpointTopic("checkpoints.internal!"));
        assertFalse(client.isCheckpointTopic("!checkpoints.internal"));
        assertFalse(client.isCheckpointTopic("source1checkpointsinternal"));
    }