With ~current CVS of both Python and Zope 3, I get 8 or 9 doctest failures when I run the zope 3 test suite with Python 2.3, both on Windows and on Linux. Most are in zope.security.tests.test_standard_checkers. I get zero failures with Python 2.2.2. --Guido van Rossum (home page: http://www.python.org/~guido/)