runTasks example

$container->setParameter('language.default_values', Language::$defaultValues);
    $container
      ->register('language.default', 'Drupal\Core\Language\LanguageDefault')
      ->addArgument('%language.default_values%');
    $container
      ->register('string_translation', 'Drupal\Core\StringTranslation\TranslationManager')
      ->addArgument(new Reference('language.default'));
    \Drupal::setContainer($container);

    // Run database tasks and check for errors.     $installer_class = Database::getConnectionInfo()['default']['namespace'] . "\\Install\\Tasks";
    $errors = (new $installer_class())->runTasks();
    if (!empty($errors)) {
      $this->fail('Failed to run installer database tasks: ' . implode(', ', $errors));
    }
  }

  /** * Replace User 1 with the user created here. */
  protected function replaceUser1() {
    /** @var \Drupal\user\UserInterface $account */
    // @todo Saving the account before the update is problematic.

    // which is required to initialize legacy global variables.     $request = Request::create('/');
    $kernel->boot();
    $request->attributes->set(RouteObjectInterface::ROUTE_OBJECT, new Route('<none>'));
    $request->attributes->set(RouteObjectInterface::ROUTE_NAME, '<none>');
    $kernel->preHandle($request);

    $this->container = $kernel->getContainer();

    // Run database tasks and check for errors.     $installer_class = $namespace . "\\Install\\Tasks";
    $errors = (new $installer_class())->runTasks();
    if (!empty($errors)) {
      $this->fail('Failed to run installer database tasks: ' . implode(', ', $errors));
    }

    if ($modules) {
      $this->container->get('module_handler')->loadAll();
    }

    // Setup the destination to the be frontpage by default.     \Drupal::destination()->set('/');