This is a very interesting topic and probably Eloy's favorite theme ;) Overall, the Ruby community strongly believes in testing, as a matter of fact we have so many testing frameworks I did not even test them all: test/unit, rspec, shoulda, bacon, context, cucumber etc.... Doing unit tests on your "models" isn't really a challenge, we probably all know how to do that and we have the tools to do so. The real challenge is to test expected behaviors at the highest level: the GUI. I talked with few very smart people during RailsConf and before that I talked to some Java friends of mine developing swing apps. It seems that everybody agrees that testing behavio(u)rs at the GUI level is really challenging. The approval testing approach is nice but it's kind of a pain since you need to validate every UI change. What would be totally awesome is a solution like Webrat + Cucumber http://cukes.info/ but for Cocoa apps developed using MacRuby. Think about it, would it be really nice if we could do something like that: Given I'm a valid twitter user When I enter my credentials Then I should see the last 50 tweets sent by my friends To do this kind of magic, we need to be able to parse the UI, the good thing is that thanks to MacRuby, we have an easy way to do full introspection on all the objects. So, in theory, we should be able to walk down the 'tree', starting at the NSApp level, pick a window, a view, an tableview, a row and check on its content after a button was clicked. This way, we can trigger UI components and see resulting behavior. We could even imagine some sort of selenium-type DSL to drive our tests in real time :) Before I get too excited, I'd like to hear what you guys think and what you believe you need to write better code? - Matt