How To Run Selenium WebDriver tests with Firefox headless mode on Ubuntu

Selenium IDE is a very good tool for recording and troubleshooting Selenium tests, but you are limited to clicking around in a GUI. For a better testing workflow, including load testing, you need to use Selenium WebDriver, which can programatically drive a browser and run Selenium test cases.

Install the official Firefox Beta PPA

$ sudo apt-add-repository ppa:mozillateam/firefox-next

(this will add the file /etc/apt/sources.list.d/mozillateam-firefox-next-trusty.list and also fetch the PPA’s key, which enables your Ubuntu system to verify that the packages in the PPA have not been interfered with since they were built)

Run apt-get update

$ sudo apt-get update

Install firefox and xvfb (the X windows virtual framebuffer) packages

$ sudo apt-get install firefox xvfb

Run Xvfb in the background and specify a display number (10 in my example)

$ Xvfb :10 -ac &

Set the DISPLAY variable to the number you chose

$ export DISPLAY=:10

Test that you can run firefox in the foreground with no errors

$ firefox

(kill it with Ctrl-C)

Now run your regular Selenium WebDriver scripts (no modifications required if they already use Firefox as their browser).

Courtesy by: 

Grig Gheorghiu (Medium)