That said, when you refactor a program in Haskell, instead of running the tests and some functionality falling, usually the compiler itself will tell you there's a problem at line X of file Y.
That use case of tests is just not there - and that's the main selling point of unit tests. Thus, I'd expect Haskell developers to not write as much of this kind of tests. But again, you'll always need some kind of it.
That said, when you refactor a program in Haskell, instead of running the tests and some functionality falling, usually the compiler itself will tell you there's a problem at line X of file Y.
That use case of tests is just not there - and that's the main selling point of unit tests. Thus, I'd expect Haskell developers to not write as much of this kind of tests. But again, you'll always need some kind of it.