title: Create fake routes to test component's link-to
body: <p>I have a component that gets menu items and renders navbar. So now I'm writing integration test, and I want to make sure, that component renders right links and labels. First of all, I added router initialization to make <code>link-to</code> display <code>href</code> prop:</p>
  
  <pre><code>moduleForComponent('main-menu', 'Integration | Component | main menu', 
  {
    integration: true,
    setup() {
      const router = getOwner(this).lookup('router:main');
      router.setupRouter();
    }
  });
  </code></pre>
  
  <p>Now I want to create some fake routes to test component, and to be independent from application router's setup. So I try to use map function:</p>
  
  <pre><code>moduleForComponent('main-menu', 'Integration | Component | main menu', {
    integration: true,
    setup() {
      const router = getOwner(this).lookup('router:main');
      router.map(function() {
        this.route('link1');
        this.route('link2');
      });
      router.setupRouter();
    }
  });
  </code></pre>
  
  <p>And I get <code>Promise rejected before "it renders": router.map is not a function</code>. So how should I implement "fake routes" for tests?</p>