I have been playing with this somewhat myself. if you use doctests and run them via the admin interface then request.function == '_TEST'. you can use that in db.py to set a different db connection string. if the population of this db is quick you can do it in the doctest itself, or come up with a way to pre-populate it. I'm still working on different ways to pre-populate my test database, and don't have anything very clean right now.
good luck! christian
