How to mock an Ember-CLI service in an acceptance test?

Question

Quick summary/tldr:

• It seems that Ember\'s container lookup process + Ember-CLI\'s module resolver doesn\'t allow manually un-registering a service and then regi

Answer 1

The existing answers work well, but there's a way that avoids renaming the service and skips the inject.

See https://github.com/ember-weekend/ember-weekend/blob/fb4a02353fbb033daefd258bbc032daf070d17bf/tests/helpers/module-for-acceptance.js#L14 and usage at https://github.com/ember-weekend/ember-weekend/blob/fb4a02353fbb033daefd258bbc032daf070d17bf/tests/acceptance/keyboard-shortcuts-test.js#L13

I'll present it here as an update to the test helper I previously had here, so it's a drop-in replacement, but you may just want to follow the links above instead.

// tests/helpers/override-service.js
// Override a service with a mock/stub service.
// Based on https://github.com/ember-weekend/ember-weekend/blob/fb4a02353fbb033daefd258bbc032daf070d17bf/tests/helpers/module-for-acceptance.js#L14
// e.g. used at https://github.com/ember-weekend/ember-weekend/blob/fb4a02/tests/acceptance/keyboard-shortcuts-test.js#L13
//
// Parameters:
// - newService is the mock object / service stub that will be injected
// - serviceName is the object property being replaced,
//     e.g. if you set 'redirector' on a controller you would access it with
//     this.get('redirector')
function(app, newService, serviceName) {
  const instance = app.__deprecatedInstance__;
  const registry = instance.register ? instance : instance.registry;
  return registry.register(`service:${serviceName}`, newService);
}

Plus performing the jslint and helper registration steps from https://guides.emberjs.com/v2.5.0/testing/acceptance/#toc_custom-test-helpers

I can then call it like this, in my example stubbing out a redirect (window.location) service, which we want to do because redirecting breaks Testem:

test("testing a redirect's path", function(assert) {
  const assertRedirectPerformed = assert.async();
  const redirectorMock = Ember.Service.extend({
    redirectTo(href) {
      assert.equal(href, '/neverwhere');
      assertRedirectPerformed();
    },
  });

  overrideService(redirectorMock, 'redirector');
  visit('/foo');
  click('#bar');
});