beforeEach(() => {
  fixture.detectChanges(); // trigger initial data binding

  // find DebugElements with an attached RouterLinkStubDirective
  linkDes = fixture.debugElement
    .queryAll(By.directive(RouterLinkDirectiveStub));

  // get attached link directive instances
  // using each DebugElement's injector
  routerLinks = linkDes.map(de => de.injector.get(RouterLinkDirectiveStub));
});