You're comparing fuzzing and property based testing. Fuzzing is a way of generating a load of random inputs for a system under test. For example if you had a f

You're comparing fuzzing and property based testing. Fuzzing is a way of generating a load of random inputs for a system under test. For example if you had a function add(a, b) -> int you'd pass in numbers, strings, bytes, whatever you want and it'll let you know if it breaks. Property based testing is similar but you check if properties hold across these values and the tool will then shrink this to the simplest case. For example you'd say that add(a, b) takes two integers and regardless of the numbers it should always have the associative property. So in fuzzing you put in junk an see what happens, in pbt you define properties and check they hold across sane inputs.