You can move models.py and views.py into seperate directories called models and views. I also make a directory to stick all my forms in called, excitingly enough, forms. But you can make a tests directory and put your tests in there. Grrr. A bit of Googling didn't get me too far, so a bit of reading of source got me this far.
The key is that Django will look to see if tests.py has a "suite" method, if so it will run it. This allows us to do what we'd like with the test runner.
So, make a directory called tests and put in it your unit tests, make a __init__.py and in that reference each of the modules you'd like to run tests on. Contents of my __init__.py:
import unittest import browser import site __tests__ = [browser, site] def suite(): suite = unittest.TestSuite() tests =  for test in __tests__: tl = unittest.TestLoader().loadTestsFromModule(test) tests += tl._tests suite._tests = tests return suite
My tests directory has a browser.py and site.py that contain unit tests. Adjust the imports and the __tests__ lists as you see fit for your instance. When I add a new file, I register it here.