use chrome since ff 47 broke tests

test/test.js

@@ -27,7 +27,7 @@ process.env.NODE_TLS_REJECT_UNAUTHORIZED = '0';
 
 describe('Application life cycle test', function () {
     this.timeout(0);
-    var firefox = require('selenium-webdriver/firefox');
+    var firefox = require('selenium-webdriver/chrome');
     var server, browser = new firefox.Driver();
     var LOCATION = 'wptest';
     var app;