rcov is what Ryan uses to generate test coverage figures for your homework:
- http://rubyforge.org/projects/rcov/
- http://github.com/spicycode/rcov/tree/master
- http://eigenclass.org/hiki.rb?rcov
(please reply if with correct links if needed)
Also, check out Heckle at: http://ruby.sadi.st/Ruby_Sadist.html