Good question - and there's been lots of work on this area. See for example property testing and fuzz testing, which can do something similar to what your second paragraph suggests.
You should be able to find a property testing library in your favourite language such as Hypothesis (python), Quickcheck (Haskell), Fastcheck (JS/typescript), etc.
You should be able to find a property testing library in your favourite language such as Hypothesis (python), Quickcheck (Haskell), Fastcheck (JS/typescript), etc.