KAFKA-12398: Fix flaky test ConsumerBounceTest.testClose

[dengziming]

More detailed description of your change
The test fails some times as follow:

We'd better use TestUtils.waitUntilTrue instead of waiting for 1 second because sometimes 1 second is too long and sometimes is too short.

Summary of testing strategy (including rationale)
for the feature or bug fix. Unit and/or integration
tests are expected for any behaviour change and
system tests should be considered for larger changes.

Committer Checklist (excluded from commit message)

• Verify design and implementation
• Verify test coverage and CI build status
• Verify documentation (including upgrade notes)

[dajac]

Could the ConsumerRebalanceListener be called if we don't poll?

[dengziming]

Sorry for the late reply, the onPartitionsAssigned is only called in AbstractCoordinator.onJoinComplete, we should call poll to invoke join onJoinComplete.

[dajac]

Make sense. So, if assignSemaphore is not released after poll is executed, it will never be released, right? Should we include poll within waitUntilTrue?

[dengziming]

That make sense, I tried to print the time cost by consumer.poll,

    println("start:" + System.currentTimeMillis() )
    consumer.poll(time.Duration.ofSeconds(3L))
    println("end:" + System.currentTimeMillis() )

and I found that poll will cost 3 seconds since no data is consumed before timeout.

start:1614844034207
end:1614844037213

We can save almost 3 seconds after moving poll to waitUntilTrue .

[dajac]

Thank for the update. Have you tried to repeatedly run the test to verify that it resolve the issue?

[dengziming]

Thank for the update. Have you tried to repeatedly run the test to verify that it resolve the issue?

@dajac Of course, I tried many times to verify, only when I set the waitTimeMs<6000 it fails occasionally.

[dajac]

LGTM, thanks for the path!