code: public function getItemHref(RunnerServiceContext $context, $itemRef)
      {
          $mapService = $this->getServiceLocator()->get(QtiRunnerMap::SERVICE_ID);
          return $mapService->getItemHref($context, $itemRef);
      }
docs: Gets AssessmentItemRef's Href by AssessmentItemRef Identifier.
  @param RunnerServiceContext $context
  @param string $itemRef
  @return string