alt Hacker NewsTechnically a property based test caught the issue.
What I've found surprising is that the __proto__ string is a fixed set from the strings sampling set. Whereas I'd have expected the function to return random strings in the range given.
But maybe that's my biased expectation being introduced to property-based testing with random values. It also feels like a stretch to call this a property-based test, because what is the property "setters and getters that work"? Cause I expect that from all my classes.
Good PBT code doesn't simply generate values at random, they skew the distributions so that known problematic values are more likely to appear. In JS "__proto__" is a good candidate for strings as shown here, for floating point numbers you'll probably want skew towards generating stuff like infinities, nans, denormals, negative zero and so on. It'll depend on your exact domain.