Most of Python packages in the Zope world use Buildout:
svn co svn+ssh://svn.zope.org/repos/main/plone.z3cform/trunk plone.z3cform cd plone.z3cform python2.4 bootstrap.py bin/buildout bin/test -pvc
Now suppose you want to change the buildout environment somehow, e.g. use the current development version of zope.testing instead of whatever is specified in buildout.cfg. Don't edit the existing buildout.cfg (you might accidentally commit your local debug changes), instead create a new cfg file, e.g. test.cfg:
[buildout] extends = buildout.cfg develop += ../zope.testing [versions] # override any existing version pins zope.testing =
Now re-run buildout
bin/buildout -c test.cfg bin/test -pvc
And the tests should be run with the newest zope.testing.code.
Only this does not work with plone.z3cform, and I have no clue why. It generally works with other packages (at least those that use the zc.recipe.testrunner rather than collective.recipe.z2testrunner). Buildout is like that sometimes :(