Are you an one man army? Congrats! :) This is great. How do you plan to react to potential changes in rendering engines? Would those be shown as test failures as well?
Great question! And yes. :) My plan at the moment for that is, because I know which browser exactly it was rendered in originally, I can put a notice at the top of the page to say something like "We just upgraded our rendering browser! The diffs below might because of that and not because of a change you made." -- and then after that one build, things would be back to normal.