Similarly, if I make a change which I don't expect to change the output of the parser, then I can use this test suite to be quite sure that my change hasn't changed behaviour.
One thing I am unclear about is what it means for klee to be "done" on my binary. When it has generated all the test cases, if none of them crash my binary, then does that mean it is impossible to crash my binary in 10 bytes of input?
Writing test harnesses specific to the different tools (so far, just AFL and KLEE) has not been particularly difficult - all of them fit easily on one screen. So I'm not sure that deepstate really brings much to the table for what I'm doing.