Last time, we saw how deleting stuff from a test case can be an easy and fun route to the root cause of a bug. It’s less easy and less fun when the test cases get big. The inner loop of test-case reduction can get old quickly: delete stuff, run the special command, check the output to decide whether to backtrack or proceed. It’s rote, mechanical, and annoyingly error prone. Let’s make the computer do it instead. Automated test-case reducers in the C-Reduce mold follow essentially the same “algor...