Zope 3 has this notion of functional doctests: functional tests (in the form of standalone doctest files) that pretend to perform HTTP requests to your Zope 3 server, and look at the response. Here's an example test from SchoolBell.
You can create functional doctests by using your browser and recording your session with TCPWatch, and then running a Python script that comes with Zope 3: dochttp. For some reason I found this method too cumbersome and usually just cloned existing doctests and changed the requests and responses by hand.
I now have a working prototype of a request recorder as a plug-in of Zope 3. You can set up a RecordingHTTP server on a separate port, and then go to /++etc++process/RecordedSessions.html to look at all requests you've made, filter them, and create a functional doctest.