DBunit seems interesting to me, I have elsewhere spoken of the early testing in development (both function and other aspects of the systems - I am trying to avoid the non-functional term as advised to Tom Gilb as it is too generic and inaccurate a term), I was pleased to see a very good talk on this at the STARWest 2005 conference, it was a good technical talk - even if it was to a minimal but grateful audience

PyUnitOSX is a build of the PyUnit Python testing framework — a Python language version of JUnit. JUnit was written by Kent Beck and Erich Gamma, and is, in turn, a Java version of Kent Beck's Smalltalk testing framework. Each is the de facto standard unit testing framework for its respective language, and therefore both are a strong basis for an effective and elegant Python framework.