title: Using karma-systemjs produces 404 for dependencies
body: <p>I'm setting up unit tests on my app. My basic test spec, <code>project.spec.ts</code>, looks like</p>
  
  <pre><code>import {Project} from './project';
  
  describe('Project', () =&gt; {
      let p = new Project('New project');
  
      it('should have the name given in the constructor', () =&gt; {
          expect(p.name).toBe('New project');
      });
  });
  </code></pre>
  
  <p><code>Project</code> is the name of the class that I am testing, and it is defined in the file <code>app/entities/project.ts</code> (i.e. in the same folder).</p>
  
  <p>However, karma produces an 404 error whenever the test spec tries to import another file:</p>
  
  <pre><code>01 03 2016 17:21:04.955:WARN [web-server]: 404: /base/app/entities/project
  Chrome 48.0.2564 (Windows 10 0.0.0) ERROR
    Error: XHR error (404 Not Found) loading C:/Dev/mps/app/entities/project
          Error loading C:/Dev/mps/app/entities/project as "./project" from C:/Dev/mps/app/entities/project.spec.js
  </code></pre>
  
  <p>It looks like the compiled file <code>project.spec.js</code> is loaded correctly, but the file project.js fails to load. Also, I can't understand where the prefix <code>/base/</code> in <code>/base/app/entities/project</code> comes from.</p>
  
  <p>A similar case is described <a href="https://github.com/rolaveric/karma-systemjs/issues/58" rel="nofollow">here</a>. However, the proposed solution does not work for me. Neither of the following import variations work:</p>
  
  <pre><code>let Project = require('./project');
  let Project = System.import('./project'); // produces "404: /project" instead
  let Project = require('./project.js');
  let Project = System.import('./project.js');
  </code></pre>
  
  <p>My configs are:</p>
  
  <p><em>karma.conf.js</em></p>
  
  <pre><code>module.exports = function(config) {
    config.set({
      basePath: '',
      plugins: ['karma-systemjs', 'karma-jasmine', 'karma-chrome-launcher'],
      frameworks: ['systemjs', 'jasmine'],
      systemjs: {
          configFile: 'system.conf.js'
      },
      files: [
        'app/entities/project.spec.js'
      ],
      exclude: [ ],
      preprocessors: { },
      reporters: ['progress'],
      port: 9876,
      colors: true,
      logLevel: config.LOG_INFO,
      autoWatch: true,
      browsers: ['Chrome'],
      singleRun: false,
      concurrency: Infinity
    })
  }
  </code></pre>
  
  <p><em>system.conf.js</em></p>
  
  <pre><code>System.config({
      paths: {
          'traceur': 'node_modules/traceur/bin/traceur.js',
          'systemjs': 'node_modules/systemjs/dist/system.js',
          'system-polyfills': 'node_modules/systemjs/dist/system-polyfills.js',
          'es6-module-loader': 'node_modules/es6-module-loader/dist/es6-module-loader.js'
      }
  });
  </code></pre>
  
  <p>What am I doing wrong?</p>