Regarding unit testing JavaScript, I recently asked this question myself at Stack Overflow (and if you're not familiar with Stack Overflow and the Stack Exchange Network, I recommend you should; it is a great place to get answers for technical problems), and ended up using Jasmine. I'm skeptical of the “BDD” thing, but it seems a perfectly fine tool for unit testing. I'm using it (example) to test logic inside the browser — that is, I load a web page which runs the tests and becomes the report of results — but I understand it can also be used from a “headless” environment of your choice.