[Zope] In zopeproject context, how can I execute test on one or all buildout-eggs packages ?

Hello, at this place https://answers.launchpad.net/zopeproject/+question/25054 I've asked this question : """ In zopeproject context, how can I execute test on one or all buildout- eggs packages ? I've tried to use bin/test -p zope.foobar but it do nothing. """ Thanks for your help, Stephane