Thanks for your suggestions on the test code. I will do that. It seems like the hard-coded approach would be more brittle. For example, if someone wants to replace __import__ with their own, e.g. old__import__ = __builtins__.__import__ def __my_logging_import(*args, **kwargs): print "Importing %s..." % args[0] # module name return old__import__(*args, **kwargs) __builtins__.__import__ = __my_logging_import Then the stack traces would be different: File "/Users/chris_g4/dev/Python/trunk/Lib/unittest/loader.py", line 92, in loadTestsFromName module = __import__('.'.join(parts_copy)) File "unittests.py", line 8, in __my_logging_import return old__import__(*args, **kwargs) ImportError: No module named sdasfasfasdf This causes the unit tests not to pass.