title: Karma closes the browser unexpectly
body: <p>Hi I am using <b><em>Karma + mocha</em></b> to write unit testcases for uicomponents like select, combobox etc... </p>
  
  <p>I am facing a problem where I have about 211 testcases but <b>Karma</b> closes the browser unexpectedly before all the testcases are run. 
  I made sure that methods such as describe.only, describe.some, describe.skip etc.. are not used.</p>
  
  <p>Screenshot of the log when I run the testcases for the first time.
  <a href="https://i.stack.imgur.com/Td8fs.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Td8fs.png" alt="second time"></a></p>
  
  <p>Screenshot of the log when I run the same testcases for the second time.
  <a href="https://i.stack.imgur.com/tScIO.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/tScIO.png" alt="first time"></a></p>
  
  <p>I have gone through some Karma code and I found out that from socket.io, <b>"browser_complete</b>" event is emitted and so karma winds up the server. Why is this happening? How can I avoid this problem?</p>