/**
  * Get an object from the fixture.
  * @param $className The data class, as specified in your fixture file.  Parent classes won't work
  * @param $identifier The identifier string, as provided in your fixture file
  */
 protected function objFromFixture($className, $identifier)
 {
     if ($this->fixture) {
         return $this->fixture->objFromFixture($className, $identifier);
     } else {
         user_error("You've called \$this->objFromFixture() but you haven't specified static \$fixture_file.\n" . "Ensure that static \"\$fixture_file = 'module/tests/fixturefile.yml';\" is specified in your " . get_class($this) . " class.", E_USER_WARNING);
     }
 }