> It would probably be simpler to change the policy and allow (at least some) some third party libs in cPython's test suite. =)

I'm actually totally okay with this, as I'd really like to have JUnit XML output from the test suite, which is easiest to do with the existing third-party libraries.

Can we formalize a way by which optional third-party libraries are allowed? Provided they aren't critical for the overall pass/fail state of the test suite (or the more strict alternative: pass/fail state of *each* test), I don't see any particular harm in certain site packages being used.

(This is probably a discussion for python-dev, assuming the policy is written down somewhere.)