Having Eclipse & JUnit in mind I missed unit testing quite a bit while developing with XCode for iPhone.
As a first shot, I set SenTestingKit up as explained by it’s author and it works really nicely. One thing I still miss is Step’n’Trace debugging the tests.
Other intros to the topic from Apple about OCUnit (2005) and SenTestingKit (2008) are ok but not as good as from the author of SenTestingKit.
Didn’t examine other Unit Test frameworks like e.g. the one from Google yet.