title: how to mock http error for angular2 testing
body: <p>I am writing unit tests for an angular2 service. Code snippets:</p>
  
  <pre><code>// jasmine specfile
  
  // already injected MockConnection into Http
  
  backend.connections.subscribe ((c: MockConnection) =&gt; {
      connection = c;
  });
  
  // doing get-request
  myServiceCallwithHttpRequest ().subscribe (result =&gt; {
      // this test passes!
      expect (result).toEqual ({
          "message": "No Such Object"
      });
      // this test fails, don't know how to get the response code
      expect (whereIsResponseStatus).toBe (404);
  });
  
  connection.mockRespond (new Response (new ResponseOptions ({
      body: {
          "message": "No Such Object"
      },
      status: 404
  })));
  </code></pre>
  
  <p>my Service:</p>
  
  <pre><code>// service
  
  myServiceCallwithHttpRequest (): Observable&lt;Response&gt; {
      return this.http.get ('/my/json-service').map (res =&gt; {
              // res.status == null
              return res.json ()
          })
          .catch (this.handleError); // from angular2 tutorial
  }
  </code></pre>
  
  <p>The first expect is OK, the program goes into the map call, not the catch. But how do I get the status code 404? res.status is null.</p>