Augment is a system for gathering metadata from code and displaying it. This metadata will include test failures, test coverage levels, complexity metrics, and others. The display frontends are pluggable so as to interface with many editors and environments.
You can gem install augment to play around with it.n
Ideally you would rarely use augment directly, but rather you would interact with it from within whatever environment you use as an editor. How you use augment is highly dependent on what editor you're using to interact with it. Augment currently supports these editors:
As you can see, that's a short list. If you'd like to implement augment support for your editor, it's pretty easy. See the writing a frontend guide for details.
Augment works by running a set of backends on a file to gather metadata about it and passing off that metadata to frontends that get feedback to the user. Currently only the test/unit backend is fully functional, but writing a backend is not that much work either. Other planned backends include:
Grab the source: git://repo.or.cz/augment.git
Hop on the mailing list to coordinate.
Augment came out of a talk from Rubyconf 2007.