Added unit tests for most of the pubsub classes that did not have any

[tishun]

Closes #2805

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• [x ] You have read the contribution guidelines.
• [x ] You have created a feature request first to discuss your contribution intent. Please reference the feature request ticket number in the pull request.
• [x ] You use the code formatters provided here and have them applied to your changes. Don’t submit any formatting related changes.
• [x ] You submit test cases (unit or integration tests) that back your changes.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 77.62%. Comparing base (43843bf) to head (347078e). Report is 241 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #2808 +/- ## ============================================ - Coverage 78.71% 77.62% -1.09% - Complexity 6786 7190 +404 ============================================ Files 508 537 +29 Lines 22765 24376 +1611 Branches 2446 2603 +157 ============================================ + Hits 17919 18922 +1003 - Misses 3717 4253 +536 - Partials 1129 1201 +72 ```

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