Added documentation about headless acceptance tests

ontrack-acceptance/README.md

@@ -101,4 +101,24 @@ Running acceptance tests against the production environment requires some heavy
 mvn clean verify -pl ontrack-acceptance -am -P it -P it-prod -DitUrl=http://ontrack.dcoraboeuf.eu.cloudbees.net -DitAdminPassword=***
 ```
 
-where `***` is the password on the `admin` account on the production environment.
+where `***` is the password on the `admin` account on the production environment.
+
+## Running tests in headless mode in Jenkins
+
+* The [Xvnc Jenkins plug-in](https://wiki.jenkins-ci.org/display/JENKINS/Xvnc+Plugin) must be installed
+* `vncserver` must be installed:
+
+        sudo apt-get install vnc4server
+
+        # Launch vncserver and enter any password
+        vncserver :11
+
+        # Copy the created .vnc configuration to your Jenkins location, for example:
+        cp -r .vnc /var/lib/jenkins
+
+        # Adjust rights accordingly to this directory
+
+* Firefox must be installed:
+
+        sudo apt-get install vnc4server
+