This seems a weak test: it verifies that the parser lets you do it, but not that it *works*; if dummy did something idiotically simple, like unconditionally setting a class, call it "ok", that controls check's reporting, it'd be more evident that the test really does test what it claims to test.  After all, if "ignore non-existent inputs" were (e.g. thanks to some bug) on by default, an unintelligible entry in inputs wouldn't produce any error.