Add tests for view helpers

### What is the problem / feature ?

There are 4 helper functions in `django_cas_ng.views` that were good candidates for testing.

### How did it get fixed / implemented ?

Wrote some basic tests to try and hit all of the functionality that these helper methods expose.

### How can someone test / see it ?

See that there are more tests running on travis (and hopefully passing)

*Here is a cute animal picture for your troubles...*

![screen shot 2010-08-29 at 10 31 22 pm1](https://cloud.githubusercontent.com/assets/824194/4926570/8c6e5b66-6534-11e4-912b-12ceec693b81.png)