anchor.diff:  ///       test('should render "Hello World", () async {
   ///         var bed = new NgTestBed<HelloWorldComponent>();
   ///         var fixture = await bed.create();
  -///         expect(controller, containsText('Hello World'));
  +///         expect(fixture.text, contains('Hello World'));
   ///       });
   ///     });
   ///
  
positive.code: ///
  ///       test('should render "Hello World", () async {
  ///         fixture = await bed.create();
  ///         expect(fixture.rootElement, containsText('Hello World'));
  ///       });
  ///
  ///       test('should render "Hello World" in all-caps', () async {
  
negative.code:   ///
    /// __Example use__:
    ///     ngTestBed = ngTestBed.addProviders([
    ///       const Provider(Foo, useClass: StubFoo),
    ///     ])
    NgTestBed<T> addProviders(Iterable<Object> providers) {
      return fork(providers: _concat(_providers, providers));
  