HDDS-10285. Remove unnecessary sleep in TestMiniOzoneCluster

[smengcl]

What changes were proposed in this pull request?

Remove unnecessary sleep in TestMiniOzoneCluster. Saves 20s in the split.

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-10285

How was this patch tested?

• Test should pass without flakiness.

[adoroszlai]

Thanks @smengcl for improving runtime.

Sleep was not needed, but intentionally used, see comment above the loop. Ideally the comment should be removed, too.

We might want to further tweak the test case to create the cluster with stopped nodes initially. It can be done in a follow-up task, since it would require MiniOzoneCluster enhancement. That task can also take care of removing the leftover "20 seconds" comment.

Test passed 100x:
https://github.com/adoroszlai/ozone/actions/runs/7761658212

[smengcl]

Thanks for reviewing and merging this @adoroszlai . Good catch I haven't removed the comment above as well.

I think a more efficient way to achieve the same test goal without having to use sleep() here is to check the endpoint after the datanode has booted up and in a stable operational state. The former is already achieved by restartHddsDatanode() since it is blocking. The for-loop won't even be necessary in this case.