What, you don't like mocking other people's code? ;)

Seriously though: yes, you end up having to mock more when writing unit tests, but unlike the other kind of mocking, I don't see it as a bad thing-- if you find yourself having to mock too many things for a given test, it's usually a sign that the code should be refactored. 

When you have time, take a look at http://blog.stevensanderson.com/2009/08/24/writing-great-unit-tests-best-and-worst-practises/ for a general overview of where I'm coming from. I also just found this more django specific post that gives some decent advice: http://tech.novapost.fr/django-unit-test-your-views-en.html