Fix race condition in reflectorRunOnce test between list completion and watch start

[Copilot]

• Identify the race condition: reflectorRunOnce test waited for lastSyncResourceVersion (set before watch starts), allowing stop() to be called before watch() was invoked; Awaitility.await().forever() doesn't actually block without .until()
• Fix reflectorRunOnce to use a CountDownLatch that signals when watch() is actually called, ensuring stop() is only called after the watch has started
• Re-add the mockResourceVersion assertion (assertThat(reflectorRunnable.getLastSyncResourceVersion()).isEqualTo(mockResourceVersion)) that was accidentally removed
• Replace Thread.sleep(1 hour) with a second CountDownLatch (watchCanReturnLatch): watch() mock awaits this latch; finally block calls stop() first then counts down the latch, ensuring the reflector sees isActive=false when watch() returns
• Verify tests pass reliably (5 consecutive runs, 12 tests each)

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: Copilot
Once this PR has been reviewed and has the lgtm label, please ask for approval from brendandburns. For more information see the Code Review Process.

The full list of commands accepted by this bot can be found here.

Details

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[brendandburns]

@copilot looks like you removed validation that the mockResourceVersion was set, and also I'm not sure the Thread.sleep() is required.

[Copilot]

@copilot looks like you removed validation that the mockResourceVersion was set, and also I'm not sure the Thread.sleep() is required.

Addressed in 373ebe0. Re-added assertThat(reflectorRunnable.getLastSyncResourceVersion()).isEqualTo(mockResourceVersion) after stop() returns.

On Thread.sleep(): it is required for two reasons. First, returning null from watch() without it causes a NullPointerException at newWatch.close() in the synchronized block (line 132 of ReflectorRunnable.run()). Second, returning an empty MockWatch without it causes the reflector to loop and call watch() a second time before stop() is effective, breaking verify(times(1)).watch(any()).

[brendandburns]

@copilot I don't like that we're just hanging this thread. I think that this is just a hacky way to make sure that the watch is ongoing before we call stop. Maybe we should just add a second countdown latch that waits until stop is called before counting down.

[Copilot]

@copilot I don't like that we're just hanging this thread. I think that this is just a hacky way to make sure that the watch is ongoing before we call stop. Maybe we should just add ...

Done in e52c5a4. Replaced Thread.sleep with a second CountDownLatch (watchCanReturnLatch). The watch() mock counts down watchCalledLatch when invoked, then awaits watchCanReturnLatch before returning a MockWatch. In the finally block, stop() is called first (sets isActive=false) and then watchCanReturnLatch.countDown() releases the mock — so the reflector always sees isActive=false when watch() returns and exits cleanly.