Actually I\'m developing a compiler plugin for Scala according to the article on http://www.scala-lang.org/node/140.
Here is the code of the plugin:
I think you're looking at mock objects (I like EasyMock, but there are many others) and some refactoring.
When you refer to your makefile, I get the impression you're using good old make. If so, might I suggest you look at something like SBT, Gradle, or, as you're coming from the Ruby world, BuildR. All of them have built in support for various scala test frameworks.