title: Grails unit tests all pass but console returns fatal error
body: <p>I have a test suite that is passing yet returning a fatal error:</p>
  
  <p><code>
  | Completed 7 unit tests, 0 failed in 0m 2s<br>
  | Error Fatal error running tests: null (Use --stacktrace to see the full trace)<br>
  | Tests FAILED  - view reports in ~/Development/Projects/myProject/target/test-reports
  </code></p>
  
  <p>Using --stacktrace doesn't provide <em>any</em> additional information. The full report shows each test case passing, as they should be. </p>
  
  <p>Has anyone encountered this before? This is my first time seeing it and I can't trace what it's from.</p>
  
  <p>EDIT: I should mention it produces this error regardless of which test-suite is run</p>