Also kill firefox before running tests

runtests.js

@@ -1,5 +1,4 @@
 // jshint esversion: 6, browser: false, node: true
-
 // This file is for automated testing, it should probably not be invoked for any other purpose.
 // It will:
 // 1. npm install
@@ -60,6 +59,11 @@ run('npm', ['install'], () => {
                 'ps -ef | grep -v grep | grep \'/usr/bin/safaridriver\'' +
                 ' | awk \'{print $2}\' | while read x; do kill $x; done'
             ], waitFor());
+
+            run('bash', ['-c',
+                'ps -ef | grep -v grep | grep \'/Applications/Firefox.app/Contents/MacOS/firefox-bin\'' +
+                ' | awk \'{print $2}\' | while read x; do kill $x; done'
+            ], waitFor());
         }
     }).nThen((waitFor) => {
         run('bower', ['install'], waitFor());