After adding a postsave signal to a model, our test suite runtime increased 5-fold! I found two ways to fix this: one in factory_boy, one in pytest.
Django together with Haystack adds a powerful free-text search capability to your applications, and is widely used. This article explains how to write safe, reliable, repeatable tests for the search features, and avoid a common gotcha with indexing objects that shouldn't be indexed.
Did some refactoring on the Intranet Binder monkeypatch library to enable temporary patches using Python's context objects. This is particularly nice for use in unit tests, where you might need to mock or stub out a component's dependencies, but you don't want those changes to be visible after your test finishes, or you only want them active for part of the test.
For about a year I've been working on our Django Binder app. It was originally designed for use in intranet applications, but much of the code is useful in Django apps of all kinds.
I've just committed a bunch of improvements from my work on the iSchool project, which I'd like to highlight to anyone interested, partly as internal documentation.