fix(alertmanager): Fix flaky TestMultitenantAlertmanager_InitialSyncFailureWithSharding#7498
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fix(alertmanager): Fix flaky TestMultitenantAlertmanager_InitialSyncFailureWithSharding#7498
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…ailureWithSharding
The test was racy because the ring lifecycler background goroutine
could re-register the instance ("instance missing in the ring, adding
it back") between the service failing and the test asserting
IsRegistered() == false.
Fix by using require.Eventually to poll for the unregistered state,
giving the stopping process time to fully unregister.
Signed-off-by: Ben Ye <benye@amazon.com>
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SungJin1212
approved these changes
May 11, 2026
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What this PR does
Fixes the flaky
TestMultitenantAlertmanager_InitialSyncFailureWithShardingtest inpkg/alertmanager.Root Cause
The test asserts
require.False(t, am.ringLifecycler.IsRegistered())immediately after the service transitions toFailedstate. However, the ring lifecycler has a background goroutine that detects the instance is missing from the ring and re-registers it ("instance missing in the ring, adding it back"). There's a race between:stopping()function unregistering the instanceIsRegistered()Fix
Replace the immediate
require.Falseassertion withrequire.Eventually, polling for the unregistered state with a 5s timeout and 100ms interval. This gives the stopping process time to fully unregister the instance.Verification
Ran the test 5 times — all pass consistently.