Add Unit Testing

[code4clouds]

Is your feature request related to a problem? Please describe.
Unit Test are essential to make sure that changes in the code are not causing adverse issues to the overall functionality

Describe the solution you'd like
Write, execute unit tests and add them to the CI

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.