I don't understand why this was down-voted. IMO, the primary value of doctests is in having example code that you know actually works and being forced to change

I don't understand why this was down-voted. IMO, the primary value of doctests is in having example code that you know actually works and being forced to change the example if the implementation changes. On the other hand, unittest is far cleaner for testing corner cases and the like. I've used both in a project quite happily (and like that Django has default support for both).