title: Selenium-webdriver doesn't open firefox from mocha in nodejs
body: <p>This simple test opens firefox browser for me: </p>
  
  <pre><code> var webdriver = require('selenium-webdriver'); 
   var driver = new
   webdriver.Builder()
       .forBrowser('firefox')
       .build(); driver.get('http://www.google.com/ncr');
  </code></pre>
  
  <p>But when I try to put this code inside mocha test, firefox is not opened:</p>
  
  <pre><code>describe("simple", function () {
      it("simple", function (done) {
          var webdriver = require('selenium-webdriver'),
              By = webdriver.By,
              until = webdriver.until;
  
          var driver = new webdriver.Builder()
              .forBrowser('firefox')
              .build();
  
          driver.get('http://www.google.com/ncr');
      })
  });
  </code></pre>
  
  <p>Code executes fine, webdriver and driver are not nulls, I don't observe any error messages, working folder is the same as in initial test. I use intellij idea mocha configuration for this. How can I fix or diagnose the problem?</p>