I needed not to chain promises but to resolve a whole bunch of them together. The documentation was sparse so it took me a while to stumble upon the solution (Ember.RSVP.all). In case you need something like that here it is.
Usage and configuration instructions for JSTestDriver are available on their website. For integration with TeamCity you’ll have to write an ant build file. But to be able to run browsers on your build agent machine you’ll have to use Xvfb. The test task in your ant file should look like the one below: