http://search.npmjs.org/#/nodeunit-watcher
A wrapper for nodeunit to provide continuous testing.
nodeunit-watcher is simply a wrapper around your existing version of nodeunit. Instead of calling nodeunit to execute tests, you execute nodeunit-watcher with your desired nodeunit options like so:
nodeunit-watcher --reporter minimal testfile.js
nodeunit-watcher calls fs.watchFile on your test files and runs a new instance of nodeunit whenever you make changes to the file specified.