This dockerfile contains the steps to create an image with firefox 43 and a virtual display for CI, ideal for protractor tests. DockerHub: https://hub.docker.com/r/albertoimpl/firefox-43-xvfb
In your CI script do not forget to attach the screen with the following commands:
Xvfb -ac :0 -screen 0 1280x1024x16 &
trap 'killall -9 Xvfb' EXIT