Test-Unit is a Python module inspired from PyUnit (https://wiki.python.org/moin/PyUnit). However, the difference is that you can give HINT as an optional parameter in case the test fails.
It was developed when I was a Teaching Assistant for Database Systems course. PyUnit has unit testing capabilties but when dealing with someone who is still studying the subject, giving them a Hint as to where they are going is very important to make them move in the right direction while auto-grading.