Hi
I recently posted a Domain Specific Language (a wrapper to Test::Unit,
actually) to make unit testing in Ruby look more "rubyish". It's still
pretty much experimental but you are welcome to give it a look and
comment back.
You can find the thread here
http://groups.google.com/group/comp.lang.ruby/browse_thread/thread/af6f20fbdfe3d09c
and a small tutorial here
http://www.theniceweb.com/JaviersBlog/2005/10/tesla-test-specific-language-for-ruby.html