title: 404 on Karma when trying to use web worker
body: <p>I'm getting the error <code>WARN [web-server]: 404: /app/workers/total.js</code> when trying to run a unit test on a web worker.</p>
  
  <p><code>Karma.conf.js</code> includes the following:</p>
  
  <pre><code>...
  files: [
          ...
          'app/workers/*.js',
          'unit-tests/mocks/**/*.js',
          'unit-tests/src/**/*.js'
      ],
  ....
  </code></pre>
  
  <p>the test goes as follows:</p>
  
  <pre><code>describe('totals', function () {
      var worker;
  
      beforeEach(function() {
          worker = new Worker('/app/workers/total.js');
      });
  
      it('should do something', function () {
          ...
      });
  });
  </code></pre>
  
  <p>I have tried many urls, but none seem to work</p>