title: Teamcity 'XML report processing' - Fail Powershell step if tests have failed
body: <p>So I'm manually importing my NUnit results and using the <strong>XML report processing</strong> build feature to process them. However I want to exit a Powershell step if any of the tests have failed (I'm destroying some instance programatically, but would rather keep them for troubleshooting if a test has failed).</p>
  
  <p>The build feature gives me:</p>
  
  <pre><code>[Step 1/1] Failed tests detected
  </code></pre>
  
  <p>How can I programatically (in powershell) detect when this is the case?</p>