code: public function useClientContainer()
      {
          if ($this->hasOption(self::OPTION_CLIENT_TESTRUNNER)) {
              return $this->getOption(self::OPTION_CLIENT_TESTRUNNER);
          } else {
              // fallback to taoQtiItem config
              $itemModel = $this->getServiceLocator()->get(ItemModel::SERVICE_ID);
              return $itemModel->getCompilerClass() == QtiJsonItemCompiler::class;
          }
      }
docs: Whenever or not to use client container for test runner
  Fallback determined by qtiItem model extension
  @return boolean