[Haskell-cafe] A question about GHC test coverage

[Olaf Klinke]

You should not have to write tests for functions you did not define. Correct me if I'm wrong, but any property of max can be derived from the properties of <=. Sadly, the laws for Ord are not stated in the documentation of Data.Ord. (Because there is no consensus?) They are:

Reflexive:
if x == y then x <= y

Transitive:
if x <= y and y <= z then x <= z

Antisymmetric:
if x <= y and y <= x then x == y

Olaf