Reusable applications and tests

I’ve often thought that I should probably be including tests with my reusable apps and projects I’ve built. I’ve never gotten around to doing that and I really think I should begin. Generally when I have a question about how I should be doing something, I turn to existing projects and see how they’re doing things.

The only problem is that I’ve not run across too many reusable Django applications that include tests.

Does anyone know any good third-party reusable Django applications that come with good tests?

P.S. I really had wished there was a section on best-practices for this sort of thing in James Bennett’s book