ZenTest provides 4 different tools: zentest, unit_diff, autotest, and multiruby. zentest scans your target and unit-test code and writes your missing code based on simple naming rules, enabling XP at a much quicker pace. zentest only works with Ruby and Minitest or Test::Unit. There is enough evidence to show that this is still proving useful to users, so it stays. unit_diff is a command-line filter to diff expected results from actual results and allow you to quickly see exactly what is wrong. Do note that minitest 2.2+ provides an enhanced assert_equal obviating the need for unit_diff autotest is a continous testing facility meant to be used during development. As soon as you save a file, autotest will run the corresponding dependent tests. multiruby runs anything you want on multiple versions of ruby. Great for compatibility checking! Use multiruby_setup to manage your installed versions. *NOTE:* The next major release of zentest will not include autotest (use minitest-autotest instead) and multiruby will use rbenv / ruby-build for version management.