[Haskell-beginners] unit tests

As I write Haskell code I find myself needing to write test code. If this test code were organized and documented, I could probably call it a set of unit tests. I'm trying to find some convention for naming functions and variables used in unit testing, deciding on location (in same module or a second module? same directory or sub-directory?), etc. Are there any Haskell community conventions? Thanks, Mike