Autotest spoiled me for immediate feedback during the development cycle. So as I was going through the Relevance functional koans for Clojure, I had a little Watchr script continually re-running the tests from the exercise at every file save. This is what that script looked like:
There's barely anything there. All it does is run the "run.sh" script that comes with the koans whenever a ".clj" file in anywhere under the "src/koans" directory is saved. It's just a simple little thing, but so very useful.
I can't say enough about the value of rapid feedback from automated tests during the learning/development cycle. The absence of context switching to manually rerun the tests is great WIN.