[piccolbo]

I am dumb -- I test at the function level. I have a theory that the likelihood of catching a bug depends on the number of lines being tested, if each can be assumed to do its job. This implies that if a line calls a function that I wrote, I need to test that function. There is some work based on Kolmogorov complexity that seems to support this but didn't go very far (I did not see any follow up papers). Maybe it's all wrong. I am biased: I wrote quickcheck for R. (by the way, fuzz testing and randomized testing are two separate things).