protected function initStorage()
    {
        /** @var DeliveryServerService $deliveryServerService */
        $deliveryServerService = $this->getServiceManager()->get(DeliveryServerService::SERVICE_ID);
        $resultStore = $deliveryServerService->getResultStoreWrapper($this->getTestExecutionUri());
        $testResource = new \core_kernel_classes_Resource($this->getTestDefinitionUri());
        $sessionManager = new \taoQtiTest_helpers_SessionManager($resultStore, $testResource);

        $seeker = new BinaryAssessmentTestSeeker($this->getTestDefinition());
        $userUri = $this->getUserUri();

        $config = \common_ext_ExtensionsManager::singleton()->getExtensionById('taoQtiTest')->getConfig('testRunner');
        $storageClassName = $config['test-session-storage'];
        $this->storage = new $storageClassName($sessionManager, $seeker, $userUri);
        $this->sessionManager = $sessionManager;
    }