Add tests

![http://media.tumblr.com/tumblr_m7or5ecmr41rter4a.gif](http://media.tumblr.com/tumblr_m7or5ecmr41rter4a.gif)

This project doesn't have any tests, so we should remedy that.
I added it to fix a problem where the outbox isn't emptied after one test and you get errors in the next.