Ember Qunit helpers not working

I have been checking ember qunit testing using ember helpers like in official documentation . checking the examples (that are not working) I can see that they use a js library

<script src="http://ift.tt/1KJWsXj"></script> 

But I cannot find this url. I guess that this library contains the expect and visit function definition. So I cannot get qunit test works. There is any place to download ember helpers js library?, are official web site examples wrong?