testing/quick is not coverage-driven and so not good at truly "interesting" input cases. It's OK for simple invariants (e.g. anything arithmetic with an inverse

testing/quick is not coverage-driven and so not good at truly "interesting" input cases. It's OK for simple invariants (e.g. anything arithmetic with an inverse) but I would not trust it to tell me anything interesting about a parser. At this stage I might even rely on the fuzzer to test simple invariants because the tooling is nicer.