Test in Dalekjs doesn't work in Chrome

I tried this code to test if in Dalekjs Documentation , assertions examples are corrects but it doesn't work in Chrome. And it expected that it runs in Chrome and not in Firefox!? Did i do something wrong or it's just an old example. Thx for help !

module.exports = {
'MDE does its thing': function (test) {
  test
    .open('http://ift.tt/1MUGUqG')
    .assert.dialogText().is.not('I am an prompt', 'Exterminate!')
  .screenshot('test.png')
  .done();

   }
 };