Called stop() outside of a test context in Ember acceptance test

I made my first acceptance test with Ember CLI. I use Ember Mirage to mock the server.

  test('create file', function(assert){
    visit('/login');
    fillIn('input[name=username]', 'Joe');
    fillIn('input[name=password]', 'foo');
    click('button');

    andThen(function() { 
      visit('/projects/files');
    });

    andThen(function(){
      assert.ok(true);
    })  
  });

The test runs successfully, but it hangs, and I am getting the following error

Uncaught (in promise) Error: Called stop() outside of a test context

at Object.stop (http://localhost:4200/assets/test-support.js:2469:10) at Class.asyncStart (http://localhost:4200/assets/vendor.js:49507:13) at asyncStart (http://localhost:4200/assets/vendor.js:41446:44) at Object.async (http://localhost:4200/assets/vendor.js:41460:7) at fulfill (http://localhost:4200/assets/vendor.js:61624:26) at handleMaybeThenable (http://localhost:4200/assets/vendor.js:61584:9) at resolve (http://localhost:4200/assets/vendor.js:61597:7) at sealed (http://localhost:4200/assets/vendor.js:61536:11)

Ajax service

I use an ajax service, which makes calls to custom api endpoints. As you can see it uses the standard JSONAPISerializer. Could be still a problem ? This is an existing app, and there is no easy way to turn off this service, to test without it.

export default Ember.Service.extend({
  // http://ift.tt/2c53FIR
  call: function(method, type, id, action, hash = null){
    var owner = Ember.getOwner(this);
    var adapter = owner.lookup('adapter:application');
    var url = adapter.buildURL(type, id) + '/' + action;
    if (hash)
      hash.data = $.extend({}, hash);
    let res ;

    return adapter.ajax(url, method, hash);

  }
});