Intermittent test failure in PersistentTopicTest.testClosingReplicationProducerTwice

As seen in

https://builds.apache.org/job/pulsar-pull-request/org.apache.pulsar$pulsar-broker/1344/testReport/junit/org.apache.pulsar.broker.service/PersistentTopicTest/testClosingReplicationProducerTwice/

org.mockito.exceptions.verification.TooManyActualInvocations: 

pulsarClientImpl.createProducerAsync(
    "persistent://prop/global/ns/testClosingReplicationProducerTwice",
    org.apache.pulsar.client.api.ProducerConfiguration@f74e835
);
Wanted 1 time:
-> at org.apache.pulsar.broker.service.PersistentTopicTest.testClosingReplicationProducerTwice(PersistentTopicTest.java:965)
But was 2 times. Undesired invocation:
-> at org.apache.pulsar.broker.service.AbstractReplicator.startProducer(AbstractReplicator.java:124)

	at org.apache.pulsar.broker.service.PersistentTopicTest.testClosingReplicationProducerTwice(PersistentTopicTest.java:965)

[ivankelly]

Found the race. The builder stuff messed up this test completely, but the race is still there. Just put a 1s sleep after creating the replicator. Problem is ultimately that the mock should be applied before creating the replicator, because the replicator calls startProducer on construction, which will fail, and the call it again after a backoff, which is where the extra invokations are.

I’ll submit a patch tomorrow.

[sijie]

The fix is contributed by @ivankelly