I have a 13 lines example doctests here that creates a mocked CMF site and tests a content type's method that requires both the "portal_properties" tool and the "portal_catalog" to work. It's very simple to mock these. Mocky, the library I wrote to support this, makes it easy.

Look at the last example here: http://danielnouri.org/blog/devel/zope/plone-doctest-in-isolation.html