title: Unable to execute tests in parallel using testng and maven surefire plugin
body: <p>Need your help as i have been struggling with parallel execution using maven. i am trying to run Testng tests in parallel, maven V3.3.9, maven-surefire-plugin V2.18.1, with the below configurations.</p>
  
  <pre><code>&lt;suiteXmlFiles&gt;
    &lt;suiteXmlFile&gt;testng.xml&lt;/suiteXmlFile&gt;
  &lt;/suiteXmlFiles&gt;
  &lt;parallel&gt;classes&lt;/parallel&gt;
  &lt;threadCount&gt;10&lt;/threadCount&gt;
  </code></pre>
  
  <p>and also tried <code>&lt;suitethreadpoolsize&gt;10&lt;/suitethreadpoolsize&gt;</code></p>
  
  <p>But, tests aren't running in parallel. i have been searching extensively for two days but couldn't get it working. Tried all the suggestions available on google!! Need your inputs to find out where i might be wrong.</p>