[YARN-8051] TestRMEmbeddedElector#testCallbackSynchronization is flakey

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.10.0, 2.9.1, 2.8.4, 3.0.2, 3.2.0, 3.1.1
• Fix Version/s: 2.10.0, 3.2.0, 2.9.2, 2.8.5, 3.0.4, 3.1.2
• Component/s: test
• Target Version/s: 2.10.0, 3.2.0, 2.9.2, 2.8.5, 3.0.4, 3.1.2
• Hadoop Flags: Reviewed
• Assignee: Robert Kanter
• Reporter: Robert Kanter
• Created: 19/Mar/18 22:47
• Updated: 14/Oct/19 15:37
• Resolved: 29/Aug/18 22:31

Description

We've seen some rare flakey failures in TestRMEmbeddedElector#testCallbackSynchronization:

org.mockito.exceptions.verification.WantedButNotInvoked: 

Wanted but not invoked:
adminService.transitionToStandby(<any>);
-> at org.apache.hadoop.yarn.server.resourcemanager.TestRMEmbeddedElector.testCallbackSynchronizationNeutral(TestRMEmbeddedElector.java:215)
Actually, there were zero interactions with this mock.

	at org.apache.hadoop.yarn.server.resourcemanager.TestRMEmbeddedElector.testCallbackSynchronizationNeutral(TestRMEmbeddedElector.java:215)
	at org.apache.hadoop.yarn.server.resourcemanager.TestRMEmbeddedElector.testCallbackSynchronization(TestRMEmbeddedElector.java:146)
	at org.apache.hadoop.yarn.server.resourcemanager.TestRMEmbeddedElector.testCallbackSynchronization(TestRMEmbeddedElector.java:109)