scalaz/scalaz — pull request #199 by etorreborre (2012-11-28 02:09:08+00:00)
Title: Added groupWhen to IndexedSeq and List

This is a specialised version of `groupByM` where `M = Id`.

I took a different name than `groupBy` because that one is already taken by Scala collections.

I also changed the specifications using the `check` method so that they use the `prop` method. `check` is deprecated because it doesn't check anything per se but just creates a new ScalaCheck property.