Category Archives: Jenkins

Running WebDriver Selenium tests on your Jenkins build server

So you have setup Jenkins as your build server and you test your project automated with Selenium WebDriver. Now you want to run the automated tests in a Jenkins job, but you get the following error:

. Caused by: org.openqa.selenium.firefox.NotConnectedException: Unable to connect to host on port 7055 after 45000 ms. Firefox console output:
. (process:26912): GLib-CRITICAL **: g_slice_set_config: assertion 'sys_page_size == 0' failed
. Error: cannot open display: :1

This post explains how to fix this. The reason is that the user that runs your Jenkins service does not have a display. Therefore there is no possibility to open a browser like Firefox.

In order the facilitate this, we will use xvfb. This is a display server that performs all graphical user interface [GUI] operations in memory and without showing any screen output.

1. Install FireFox on the machine that runs Jenkins
In /etc/apt/sources.list add the following line.


Run the following commands to upgrade or install latest version of Firefox to work with Selenium.

sudo apt-get update
sudo apt-get install firefox

2. Install Xvfb on your server
Run the following command to install Xvfb on your server

apt-get install xvfb x11-xkb-utils xfonts-100dpi xfonts-75dpi xfonts-scalable xfonts-cyrillic x11-apps

3. Install Xvfb in Jenkins
Install the Xvfb plugin
Schermafbeelding 2015-06-21 om 19.28.28

Configure the plugin via Manage Jenkins / Configure System
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4. Configure Xvfb in your Jenkins job
Schermafbeelding 2015-06-21 om 20.45.54