Validation/Testing

[jakharkaran]

• Add unit tests to catch exceptions
• Integrate GitHub actions (YAML file)
• Add more tests as needed

Helpful links:
https://docs.pytest.org/en/7.1.x/contents.html
https://github.blog/2022-02-02-build-ci-cd-pipeline-github-actions-four-steps/
https://docs.github.com/en/actions