I think what the above returns depends on the language. In java I think there is an actual run time exception for this. The point of the original comment is to

I think what the above returns depends on the language. In java I think there is an actual run time exception for this. The point of the original comment is to show how 100% coverage is easy to achieve but often meaningless. There is some other more abstract concept related to the classes of input that can possibly be passed to a method. IMHO 100% coverage and "test first" have done more harm than good to the cause of automated testing.