fix flaky test assertions in org.apache.helix.rest.server.TestPerInstanceAccessor#testGetAllMessages

[hofi1]

Issues

• My PR addresses the following Helix issues and references them in the PR description:

Fixes #2667

Description

This fix changes the flaky assertions of the tests in the class org.apache.helix.rest.server.TestPerInstanceAccessor#testGetAllMessages.
Sets return the elements in a non-deterministic order, which means that this assertion is not correct, because it checks whether the collections contain the same elements in the same order (this was changed in the library). This leads to a flaky test.

helix/helix-rest/src/test/java/org/apache/helix/rest/server/TestPerInstanceAccessor.java

Lines 329 to 330 in bd1d28c

	Assert.assertEquals(instances, _instancesMap.get(CLUSTER_NAME), "Instances from response: "
	+ instances + " vs instances actually: " + _instancesMap.get(CLUSTER_NAME));

To fix this problem, the assertion has been rewritten to check if the collections contain the same amount of elements as well as both collections contain all values of the other collection.

helix/helix-rest/src/test/java/org/apache/helix/rest/server/TestPerInstanceAccessor.java

Lines 328 to 332 in e0b1834

	String errorMessage = "Instances from response: "+ instances + " vs instances actually: "
	+ _instancesMap.get(CLUSTER_NAME);
	Assert.assertEquals(instances.size(), _instancesMap.get(CLUSTER_NAME).size(), errorMessage);
	Assert.assertTrue(instances.containsAll(_instancesMap.get(CLUSTER_NAME)), errorMessage);
	Assert.assertTrue(_instancesMap.get(CLUSTER_NAME).containsAll(instances), errorMessage);

The flaky test has been found by using the NonDex tool – to reproduce run

mvn -pl helix-rest edu.illinois:nondex-maven-plugin:2.1.1:nondex -Dtest=org.apache.helix.rest.server.TestPerInstanceAccessor -DnondexSeed=933178

Tests

No test have been written – one existing test has been updated.

• The following is the result of the "mvn test" command on the appropriate module:
  [INFO] ------------------------------------------------------------------------
  [INFO] BUILD SUCCESS
  [INFO] ------------------------------------------------------------------------
  [INFO] Total time: 01:23 min
  [INFO] Finished at: 2023-10-17T22:47:43-05:00
  [INFO] ------------------------------------------------------------------------

[desaikomal]

thanks for working on this.