title: Coverage in WebStorm with Mocha doesn't work
body: <p>I followed this guide to get coverage report integrated in WebStorm. </p>
  
  <p><a href="https://www.jetbrains.com/help/webstorm/mocha.html" rel="nofollow noreferrer">https://www.jetbrains.com/help/webstorm/mocha.html</a></p>
  
  <p>When I click "Run Mocha test with coverage" the coverage window shows up after running the test. But I don't see any coverage reported. It is not even showing 0%, it is not showing any numbers at all in the Statistics column. </p>
  
  <p>Any help will be appreciated. </p>
  
  <p>Some more background:</p>
  
  <ul>
  <li>WebStorm 2017.2.3</li>
  <li>I'm referring Mocha v3.2.0 in package.json</li>
  <li>The code is written in ES2015.</li>
  <li>The mocha Run configuration uses these environment variables </li>
  </ul>
  
  <blockquote>
    <p>BABEL_ENV=test and these extra mocha options: --compilers
    js:babel-core/register</p>
  </blockquote>
  
  <p>Thanks in advance</p>
  
  <p>Further information: when I run with coverage in WebStorm I see this command being output to the console: </p>
  
  <blockquote>
    <p>/Users/nikolaschou/.nvm/versions/node/v8.1.2/bin/node /Users/nikolaschou/Dev/dsg/bifrostshop/node_modules/nyc/bin/nyc.js --reporter=lcovonly --extension=.ts --extension=.js --exclude=test/unitmocha/<strong>/<em>.spec.</em> --exclude=test/unitmocha/</strong>/<em>.test.</em> --report-dir=/private/var/folders/q7/kn0zjzks5dz0q2bx0kpg2yhw0000gn/T/mocha-intellij-coverage- /Users/nikolaschou/Dev/dsg/bifrostshop/node_modules/mocha/bin/_mocha --compilers js:babel-core/register --ui bdd --reporter "/Applications/WebStorm 2.app/Contents/plugins/NodeJS/js/mocha-intellij/lib/mochaIntellijReporter.js" --recursive /Users/nikolaschou/Dev/dsg/bifrostshop/test/unitmocha</p>
  </blockquote>