[Zope] Running Tests on my Zope Product in Zope 2.13

Hello again Zopistas! While I am on the topic of Zope 2.13, could someone please tell me how I can run my tests on my (old style, not egg) Zope Products in Zope 2.13? It seems that `zopectl test` went away without leaving more than a note on the tab^W^W^Win the CHANGES.txt log: "Removed the test command from zopectl. The test.py script it was relying on does no longer exist." So, how do I run my tests now? Thanks for any hints! Regards, Sascha