py.test is a simple but powerful tool for writing and running tests. cdent chose to use it for TiddlyWeb because PyUnit just seemed too crufty and noisy. Early code for TiddlyWeb was written test first and py.test made that a painless process.

You can get it from http://codespeak.net/py/dist/test.html where they have some quickstart instructions.

py.test -h

will reveal some help. -x and -s are useful.