title: Karma code coverage always shows 100% (0/0) for the tests
body: <p>I am trying to build a react boilerplate so that I can use it for my personal project. Right now, I am trying to integrate the code coverage feature. I want all the test files to reside in its respective component folder rather than creating a separate tests folder. Below is the link to the repo.</p>
  
  <p><a href="https://github.com/shettyrahul8june/react-webpack-beej" rel="nofollow noreferrer">https://github.com/shettyrahul8june/react-webpack-beej</a></p>
  
  <p><strong>karma.conf.js</strong></p>
  
  <pre><code>import webpackConfig from './webpack.config';
  
  webpackConfig.devtool = 'inline-source-map';
  
  module.exports = (config) =&gt; {
    config.set({
      browsers: ['Chrome'], // run in Chrome
      singleRun: true, // just run once by default
      colors: true,
      // autoWatch: true,
      // logLevel: config.LOG_DEBUG,
      // use the mocha, chai and sinon test framework
      frameworks: ['mocha', 'chai', 'sinon'],
      files: [
        'tests.webpack.js', // just load this file
      ],
      preprocessors: {
        // preprocess with webpack and our sourcemap loader
        'tests.webpack.js': ['webpack', 'sourcemap'],
      },
      plugins: [
        'karma-chrome-launcher',
        'karma-chai',
        'karma-mocha',
        'karma-sinon',
        'karma-sourcemap-loader',
        'karma-webpack',
        'karma-coverage',
      ],
      // report results in this format
      reporters: ['progress', 'coverage'],
      coverageReporter: {
        dir: '../coverage',
        reporters: [
          { type: 'text-summary' },
          { type: 'html' },
          { type: 'lcov' },
        ],
      },
      webpack: {
        node: {
          fs: 'empty',
        },
        module: webpackConfig.module,
        resolve: webpackConfig.resolve,
        externals: Object.assign({}, webpackConfig.externals, {
          'react/addons': true,
          'react/lib/ExecutionEnvironment': true,
          'react/lib/ReactContext': 'window',
        }),
      },
      webpackServer: {
        noInfo: true, // please don't spam the console when running in karma!
      },
    });
  };
  </code></pre>
  
  <p>test.webpack.js</p>
  
  <pre><code>// make sure you have your directory and regex test set correctly!
  const context = require.context('../src/', true, /.+\.test\.jsx?$/);
  context.keys().forEach(context);
  </code></pre>
  
  <p>I tried going through various questions which are similar to mine but none actually solve my problem. Most of them have configured in a different way. I am not sure what am I doing wrong. I tried various techniques but all efforts where in vain. Test seems to work fine but the coverage always shows 100%.</p>