JS unit testing: run tests on file changes (like nodemon)

I have two question on JS unit testing:

1) Is there some tool that allows to automaticaly run javascript unit tests when certain files are changed (like for example nodemon restarts node.js on js changes).

2) Is this strategy appropriate (efficient) way to run unit tests?

Thanks, Alex

javascript
unit-testing
node.js
testing

For those who are committed to using nodemon, nodemon -x "npm test" has worked for me.

A little explanation

nodemon --help says:

-x, --exec app ........... execute script with "app", ie. -x "python -v".

In our case npm test is set to run tests by configuring our package.json

For example:

"scripts": { "test": "mocha" },

Check out grunt build system and the watch task. You can setup grunt to watch for file changes and then run any tasks you want (test, lint, compile, etc...).

https://github.com/cowboy/grunt

Some of the ideas are covered in this tutorial. http://javascriptplayground.com/blog/2012/04/grunt-js-command-line-tutorial