Add test for MultiBucketStrategy class

[yashpal2104]

Testing done

Add test for MultiBucketStrategy class and Made getStrategy method package-protected and condition for non-integer input.

Submitter checklist

• Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
• Ensure that the pull request title represents the desired changelog entry
• Please describe what you did

[yashpal2104]

Should I replace the numbers with the variable I have declared DEFAULT _PRIORITIES_NUMBER and DEFAULT_PRIORITY for improved readability and clean code?

[MarkEWaite]

Should I replace the numbers with the variable I have declared DEFAULT _PRIORITIES_NUMBER and DEFAULT_PRIORITY for improved readability and clean code?

Thanks for asking a very, very good question. When I reviewed the code the first time, I didn't consider your question. A second review in the context of your question made the test code clearer for me. Thanks!