Add unit & integration tests

[Omranic]

[ebisbe]

Can I help in some way? @Omranic @ionut-tanasa

[Omranic]

@ebisbe Yes, yes, yes please 🙏 That would greatly help us release next version faster, we need to cover all functions with test suites, update missing parts in the docs and release it 😄 Appreciated in advance 👍

[ebisbe]

@Omranic ok, but thats a vague description of all the work. Where do I start?

[Omranic]

Honestly I still didn't scan for what's already implemented and what's missing, so if you can find your way inside the tests directory that would be easier and faster than waiting me analyze our current state 😅 @evsign & @ionut-tanasa who already worked thanksfuly on this before