diff -r e750e5abd1c7 -r bff36e86f74a devtools/qunit.py
--- a/devtools/qunit.py	Wed Apr 10 15:34:18 2013 +0200
+++ b/devtools/qunit.py	Thu Apr 11 10:32:00 2013 +0200
@@ -70,7 +70,8 @@
         stderr = TemporaryFile()
         self.firefox_cmd = ['firefox', '-no-remote']
         if os.name == 'posix':
-            self.firefox_cmd = [osp.join(osp.dirname(__file__), 'data', 'xvfb-run.sh'), '-a'] + self.firefox_cmd
+            self.firefox_cmd = [osp.join(osp.dirname(__file__), 'data', 'xvfb-run.sh'),
+                                '-a', '-s', '-noreset -screen 0 640x480x8'] + self.firefox_cmd
         try:
             home = osp.expanduser('~')
             user = getlogin()