Renamed class "Request" to "FakeRequest".
Refactored Playlist model tests. (Plus a small change in utils views test.)
Refactored profile model tests. (Also, made some slight changes in playlist model tests.)
Merge branch 'refactor-tests'

I refactored the model tests. The main idea was to mock out as many assets as possible.
In addition, I renamed the class "Request" to "FakeRequest" in the utils view tests.