Test driven development will help in a few aspects when developing an application. One aspect is you get to eat your own dog food even before you make it. You are able to use your API's before they are implemented, this will display any short comings in the design. Also by forcing yourself to think through a problem and get a better understanding, which in turn helps make better design decisions. We all make mistakes, without testing our code base there is no way to be sure that everything is still working, otherwise you are crossing your fingers and knocking on wood.
Django and Python Test Tools
If you've been using Django for some time you have heard the phrase "Django is just Python" and this holds true in the realm of testing your Django Application. You can use other testing frameworks with Django like nose. Django comes with a good testing framework that is built off the Python unittest module. The default Django testcase is a subclass of unittest.TestCase this class provides with some additional assertions and also a client that will helps you test your views ( more details to come ).
