Unit testing in place of learning

(tags programming, unit testing, library, Ruby, Emacs Lisp)

I've been "test-infected" by Ruby's Test::Unit library. I wanna get the same kicks in Emacs Lisp. I wrote up the RubyGarden UsingTestUnitToLearnRuby. I rewrote the EmacsWiki UnitTesting page and I'm now trying to decide between regress.el and ElUnit. Both aren't as expressive as Test::Unit, but ElUnit surely looks promising. Except it doesn't have unit tests for itself. Huh.