Update .travis.yml

Start the xvfb service

.travis.yml

@@ -4,6 +4,9 @@ language: python
 python:
   - 2.7
 
+addons:
+  firefox: "latest"
+
 services:
   - docker
 
@@ -13,9 +16,13 @@ before_install:
 install:
   - docker run --rm -t -v "$TRAVIS_BUILD_DIR:/tmp/pandorafms" -p 80:80 pandorafms/pandorafms-base /tmp/pandorafms/tests/test.sh
   - pip install selenium PyVirtualDisplay
+
+before_script:
+  - "export DISPLAY=:99.0"
+  - "sh -e /etc/init.d/xvfb start"
+  - sleep 4 # give xvfb some time to start
   
 script:
   - python $TRAVIS_BUILD_DIR/tests/console/PAN1.py
 
-addons:
-  firefox: "latest"
+