title: Karma Jasmine unit testing with Angular 4 is caching
body: <p>I comment out code in a spec file and it is still failing my test.  </p>
  
  <ol>
  <li>why is it like this?</li>
  <li>what can I do about this ,  edit karma config file with something????</li>
  </ol>
  
  <p>So here is a snippet of what I commented out</p>
  
  <pre><code>it('Should find trackerId in the session tracker slider panel', () =&gt; {
      let sessionTrackerfixture = TestBed.createComponent(TrackerFormTemplateComponent);
      let sessionTrackerapp = sessionTrackerfixture.debugElement.componentInstance;
      sessionTrackerapp.model.session = '1234567890-1-1';
      sessionTrackerfixture.detectChanges();
      let compiled = sessionTrackerfixture.debugElement.nativeElement;
      expect(compiled.querySelector('.session').textContent).toContain('1234567890-1-1');
  });
  </code></pre>
  
  <p>It still shows up </p>
  
  <pre><code>TrackerFormTemplateComponent Should find trackerId in the session tracker slider panel
  </code></pre>