Setup CI automated tests + code coverage

[pavel-karatsiuba]

Add tests for each *.ts file and function with business logic.
More tests more stability.

[kelson42]

Agree on the principle. That said this type of ticket is going to live long and the goal is not make short step progresses. To me the most important at this stage is to have a CI with automated test + test coverage. Once this is done, any further development should include proper automated tests, with "unit tests" first.