automatic debugging

saw some interesting work on automatic debugging. the idea is to use tests (passing tests with one failing tests) to evaluate random code changes and find one that works. i don't really expect my computer to debug my code any time soon. but one interesting thought was that the ast nodes to change were weighted by positive and negative test coverage. maybe i could use coverage in this one to localize a bug. (more likely is places covered by multiple negative tests, less likely in places covered by positive tests.) that would help me find the bug, which is almost always the hardest part. refs to the spike black-box fuzzer from immunitysec.com, strata dynamic binary transformation (from virginia).