Wow, it looks like a really slick OS. I think it'll be neat seeing web-apps as first class citizens - it never made sense to me why we have to use Objective-C or Java just to make some UI or whatever.
Mozilla's talk about testing FirefoxOS, at the Google Test Automation Conference last week: http://www.youtube.com/watch?v=X41eqcmC2Dk
Writeup: http://lwn.net/SubscriberLink/548910/9c5d6bd1bd69f34c/
Demo of automated UI test using Appium to test an app on the FirefoxOS simulator: http://www.youtube.com/watch?v=1J0aXDbjiUE#t=34m30s