Unit/integration tests for major features

[schlessera]

The testing framework is now included in master and we should try to write a few tests for each of the major features for some basic sanity checking.

[swissspidy]

IMHO this can happen outside of a specific release. I doubt that we want to ship tests with the version on dotorg.

[Zodiac1978]

As no one has tried to implement this until now I move this to the v3