Therefore this approach is preferable

This does a better job covering good and bad cases in the implementation,
though currently none of the values resulting are used so they're still not actually covered.

not sure if it is a good idea to combine them though

It's sort of a meaningless change.  Blech.

on advice of #haskell, going to try hedgehog instead

This compiles but tests fail.  The perfect stopping point.

I dunno if this is a good idea or not but it helps the build succeed on my system.