Sounds like your asking for a protocol-level capture/replay functional
testing framework.
Check out the thread Jason Sweat started in ruby-talk 130044 or
(http://groups.google.com/group/comp.lang.ruby/browse_thread/thread/20552f77c95bde64/)
Wee's WWW::Mechanize port is probably the most fitting. If it's
web-application testing you're doing, I have to plug the Systir + Watir
combo. (http://atomicobject.com/systir.page)