inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
   let responses: Response[] = [sampleResponse1, sampleResponse2];
   backend.connections.subscribe((c: MockConnection) => c.mockRespond(responses.shift()));
   let responseObservable: ReplaySubject<Response> =
       backend.createConnection(sampleRequest1).response;
   responseObservable.subscribe(res => expect(res.text()).toBe('response1'));
   responseObservable.subscribe(res => expect(res.text()).toBe('response2'), null,
                                async.done);
 }));

 /**
  * Sends a mock response to the connection. This response is the value that is emitted to the
  * {@link EventEmitter} returned by {@link Http}.
  *
  * ### Example
  *
  * ```
  * var connection;
  * backend.connections.subscribe(c => connection = c);
  * http.request('data.json').subscribe(res => console.log(res.text()));
  * connection.mockRespond(new Response('fake response')); //logs 'fake response'
  * ```
  *
  */
 mockRespond(res: Response) {
   if (this.readyState === ReadyState.Done || this.readyState === ReadyState.Cancelled) {
     throw new BaseException('Connection has already been resolved');
   }
   this.readyState = ReadyState.Done;
   this.response.next(res);
   this.response.complete();
 }

 // TODO(jeffbcross): consider using Response type
 /**
  * Emits the provided error object as an error to the {@link Response} {@link EventEmitter}
  * returned
  * from {@link Http}.
  */
 mockError(err?: Error) {
   // Matches XHR semantics
   this.readyState = ReadyState.Done;
   this.response.error(err);
 }