[GOBBLIN-2160] added some unit tests for gobblin temporal module

[pratapaditya04]

Dear Gobblin maintainers,

Please accept this PR. I understand that it will not be reviewed until I have checked off all the steps below!

JIRA

• My PR addresses the following Gobblin JIRA issues and references them in the PR title. For example, "[GOBBLIN-XXX] My Gobblin PR"
  • https://issues.apache.org/jira/browse/GOBBLIN-2160

Description

• Here are some details about my PR, including screenshots (if applicable):
  Added Unit tests for JobStateUtils and AbstractNestingExecWorkflowImpl classes in Gobblin-temporal module

Tests

• My PR adds the following unit tests OR does not need testing for this extremely good reason:

Commits

• My commits all reference JIRA issues in their subject lines, and I have squashed multiple commits if they address the same issue. In addition, my commits follow the guidelines from "How to write a good git commit message":
  1. Subject is separated from body by a blank line
  2. Subject is limited to 50 characters
  3. Subject does not end with a period
  4. Subject uses the imperative mood ("add", not "adding")
  5. Body wraps at 72 characters
  6. Body explains "what" and "why", not "how"

[khandelwal-prateek]

I understand that you added @VisibleForTesting and changed modifier to public for testing this method. However, this change is not required if we follow the same package structure for the test class and we can access protected methods without exposing them publicly. We can revert the modifier change and place the test class in the same package instead.

[khandelwal-prateek]

update package to org.apache.gobblin.temporal.util.nesting.workflow

[khandelwal-prateek]

I see you've covered some scenarios, like handling an empty WorkSpan and testing the pause duration. However, the current tests don't fully capture the functionality(creating child workflows, subtrees handling, result calculation and edge cases) of the performWorkload method. It would be useful to add overall coverage for a method when we are adding tests for it, this ensures that the tests fulfill the original intent of thoroughly validating the behavior of missing tests. This would also help avoid the need for additional work on this method again later, unless we are making changes to it.