elidupree
commented
3 years ago "Luckily, when this precondition failure occurred, we were already running tests for the containing function, function_name(). So this failure is likely to be the fault of function_name(). Suggested regression test:"
"This precondition failure occurred, inside function_name(), so this failure is likely to be the fault of function_name(). Unfortunately, we weren't running tests for function_name() at the time, so we didn't record the inputs to it."
"...but fortunately, we DID record the inputs to another, outer containing function, third_function_name():"
Currently, precondition failures never know what to blame or how to make a regression test.
Live-prop-test could keep an internal call stack, and thus blame the failure on the next tested function outside the one which failed a precondition.
...Except that we didn't necessarily record the inputs to that function.
...But if it happens that we did, shouldn't we take advantage of that?
It would be a little flaky (e.g. we can't necessarily guarantee that it wasn't caused by a failure in an outer precondition that wasn't checked), but we could just mention that in the error message that occurs in this case.