Calling visit() in acceptance test for Ember 2.2.0 times out

New Ember developer coming from a Rails world. Developing my first Ember client side app to interact with a Rails app for our API endpoint.

Using Ember 2.2.0, ember-cli, ember-cli-mirage 0.1.11, and PhantomJS 2.0.0, somehow, when calling visit('/facilities') in an acceptance test, all I get is a timeout.

My app/mirage/config.js file seems to be properly set up with the following:

export default function() {
  this.get('/facilities');
  this.get('/facilities/:facility_id');
}

Is there anything I'm missing?