Ember tests: How can I pause a test until some content is rendered?

I'm trying to create a simple test for creating of new record.

test('Create dataset', function(assert) {
  expect(1);
  visit('/add');

  fillIn('input.name', 'some name');
  fillIn('input.description', 'some description');


  //this part is to click on custom dropdown and select first option
  click('.select2-container input'); //after this action a list of options is generated
  click('.select2-drop ul li:first'); //but this action runs before the list was generated, so it gives me an error that this element does not exist

  click('button[type="submit"]');

});

Is there any way to pause the test untill the list as rendered?

For example something like waitFor('.select2-drop ul li:first')