title: angular2 testing framework async testing issue
body: <p>I have created angular 2 a project and a service with angular-cli and tried to test my service.</p>
  
  <p>But API does not fail in async function although it should fail ;moreover, it just ignores those exceptions.</p>
  
  <pre><code>/* tslint:disable:no-unused-variable */
  
  import {
    beforeEach, beforeEachProviders, describe, xdescribe,
    expect, it, xit, async, inject, injectAsync
  } from '@angular/core/testing';
  import { SearchService } from './search.service';
  import {provide} from '@angular/core';
  import {MockBackend, MockConnection} from '@angular/http/testing';
  import {XHRBackend, Response, ResponseOptions, HTTP_PROVIDERS} from '@angular/http';
  
  describe('Search Service', () =&gt; {
    let searchService: SearchService;
    let mockBackend: MockBackend;
  
    beforeEachProviders(() =&gt; [
      HTTP_PROVIDERS,
      MockBackend,
      provide(XHRBackend, { useClass: MockBackend }),
      SearchService
    ]);
  
    beforeEach(injectAsync([SearchService, MockBackend], (s, m) =&gt; {
      searchService = s;
      mockBackend = m;
    }));
  
    it('async test', () =&gt; {
      setTimeout(() =&gt; {
        expect(2).toBe(1);
      }, 3000);
    });
  </code></pre>
  
  <p>It just ignores those minimal test case. </p>
  
  <p>Then I have read some doc and updated my code as follow.</p>
  
  <pre><code>it('async test with done', (done) =&gt; {
    setTimeout(() =&gt; {
      expect(1).toBe(1);
      done();
    }, 1000);
  });
  </code></pre>
  
  <p>But this time, the test fails although it should pass. The error is as follow.</p>
  
  <p><strong>Error: Timeout - Async callback was not invoked within timeout specified by jasmine.DEFAULT_TIMEOUT_INTERVAL.</strong></p>
  
  <p>I change default timeout value to bigger value but it is no effect.</p>