[Haskell-beginners] overload a function

I would like to have a function that can accept more than one input type and gives the same back as output. For the different eligible input types there would be different tests. An example of the idea would be something like: test :: a -> Bool -> a test 0 True = 0 test False True = False . . . is it obligatory that I create a typeclass for test and then instance each type that might go in the "a" slot? Because that seems like a lot of work. Let me also add a general thank to those of you who support the beginners' list. I learn something everyday.