fix: fix flaky test in org.apache.helix.rest.server.TestInstancesAccessor

[hofi1]

Issues

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

Fixes apache#2644

Description

This fix changes the assertion of the tests. 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 leads to a flack test. To fix this problem, the assertion has been rewritten to check if the collections contain the same amount of elements as well as booth collections contain all values of the other collection.

This problem was found by the NonDex Engine – to reproduce run

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

Tests

There have been no tests added, one test condition was changed.

• The following is the result of the "mvn test" command on the appropriate module:

[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 02:54 min
[INFO] Finished at: 2023-10-04T23:01:45-05:00
[INFO] ------------------------------------------------------------------------

[harshith2000]

Please correct the spelling.
Otherwise, this fix LGTM!

[wuh3]

The desciption is brief and clear. The fix is also optimal. It Looks Good To Me.

[hofi1]

@wuh3 @harshith2000 thank you!

[zzjas]

You can consider if it makes sense to combine some of your PRs for helix into a larger one.

You can proceed to open a real PR. Once you open a real PR, please mark this tentative PR as Opened in your tentative_pr.csv file and also raise a PR to IDoFT marking this as Opened. Thanks!