How to do (unit) testing of Drupal specific JavaScript code? For PHP code in custom module, we use SimpleTest. But how do you test the JavaScript code in a module or a theme?

I known about JavaScript testing frameworks like Jasmine or QUnit, but I'm curious to known if and how they are used to test Drupal specific JavaScript code.
Right now we don't have any automated testing of the UI. There have been talks about using Selenium and there is even a proposed session about it for DrupalCon London, but i don't know of any work that has been done yet.

This could be a nice contribution for Drupal 8.