Implement proper unit tests

[rexblack]

One thing which makes this gem difficult to maintain is that it's lacking of proper unit tests, particularly in regard to the complexity of its requirements.

Since there's lots of different aspects involved ranging from tricky calendar stuff, advanced forms, ui components, database topics and lots more, some help on the topic would be highly appreciated.

Besides implementing the actual tests, an outline of the specs would also be a very helpful starting point. Contributions welcome!

[nekapoor]

I'm looking to get better at Rails and, in particular, writing tests. I think with my skillset, I need a bit of direction on specific tests that need to be written. But if there are specific to-dos, I'd be more than happy to help out.