Add unit tests again

[johanv]

This is probably not the most urgent issue, but I add it for the sake of completeness :-)

Detlef used to have unit tests, but in the working branch they are deleted in 30E360. It would be cool if we could reintroduce unit test projects, because they can prevent us from making the same mistakes over and over again.

[schuay]

Looks good, I'll pull this once you're done.

[johanv]

I've put this on hold for a while. Right now I am fixing the issues that annoy me, to make detlef more useful on my phone :-)

I still think tests are important. I could have added tests for the issues I've been fixing. But for the moment, I think making detlef work for me is more important.