while trying to implement pep8-testing for nose (using tissue, which didn't work for me), I just tried runnin whoosh's tests with py.test: it works without a problem (as far as i could see).
py.test has some nose-compatibility: http://pytest.org/latest/nose.html
py.test has a great and time-saving pep8 plugin: http://pypi.python.org/pypi/pytest-pep8 (I have thrown away my own pep8-sourcecode-test-hack in favour of that one!)
py.test has maybe some other nice advantages (I personally don't have much experience with nose, so I am referring to some external sources):
We are using py.test since long for moin 1.x and moin 2. We are very happy with it as it is quite flexible, tests are easy to write and it tries to help you if a test fails (showing what exactly failed). We didn't use nose before though, we came (long long ago) from unittest (which was quite unpopular within our developers).
If you like py.test, i can help switching to it, just tell.