class ConfigurableLanguageManagerSwitchLinksTest

class ConfigurableLanguageManagerSwitchLinksTest extends UnitTestCase {
  
  /**
   * Test that change of negotiated languages stays in getLanguageSwitchLinks().
   */
  public function testSwitchLinksFiberConcurrency() : void {
    // Mock two languages and a URL per language for use in the language switch
    // links.
    foreach ([
      'de',
      'en',
    ] as $langcode) {
      $languages[$langcode] = $this->createMock('\\Drupal\\Core\\Language\\LanguageInterface');
      $languages[$langcode]->method('getId')
        ->willReturn($langcode);
      // ConfigurableLanguageManager::getLanguageSwitchLinks() changes the
      // negotiated language to the language of each link before checking access
      // to the link's URL. If this is running in a fiber, it is possible that
      // calling ::access() on the URL object can suspend the fiber, if entities
      // are loaded as part of the access check. Simulate this in the mock URL
      // object by forcing the fiber to be suspended in ::access();
      $urls[$langcode] = $this->createMock(Url::class);
      $urls[$langcode]->method('access')
        ->willReturnCallback(function () {
        if (\Fiber::getCurrent() !== NULL) {
          \Fiber::suspend();
        }
        return TRUE;
      });
    }
    // Create mock objects needed to instantiate ConfigurableLanguageManager.
    $negotiationMethod = $this->createMockForIntersectionOfInterfaces([
      LanguageNegotiationMethodInterface::class,
      LanguageSwitcherInterface::class,
    ]);
    $negotiationMethod->method('getLanguageSwitchLinks')
      ->willReturnCallback(function () use ($languages, $urls) {
      $links = [];
      foreach ($languages as $langcode => $language) {
        $links[$langcode] = [
          'language' => $language,
          'url' => $urls[$langcode],
        ];
      }
      return $links;
    });
    $negotiator = $this->createMock(LanguageNegotiatorInterface::class);
    $negotiator->method('getNegotiationMethods')
      ->with(LanguageInterface::TYPE_INTERFACE)
      ->willReturn([
      'language-test-fiber' => [
        'class' => $negotiationMethod::class,
      ],
    ]);
    $negotiator->method('getNegotiationMethodInstance')
      ->with('language-test-fiber')
      ->willReturn($negotiationMethod);
    $defaultLanguage = $this->createMock(LanguageDefault::class);
    $defaultLanguage->method('get')
      ->willReturn($languages['en']);
    $configFactory = $this->createMock(ConfigFactoryInterface::class);
    $configFactory->method('listAll')
      ->willReturn([]);
    $configFactory->method('loadMultiple')
      ->willReturn([]);
    $requestStack = $this->createMock(RequestStack::class);
    $requestStack->method('getCurrentRequest')
      ->willReturn($this->createStub(Request::class));
    // Instantiate the language manager and initialize the negotiator.
    $languageManager = new ConfigurableLanguageManager($defaultLanguage, $configFactory, $this->createStub(ModuleHandlerInterface::class), $this->createStub(LanguageConfigFactoryOverrideInterface::class), $requestStack, $this->createStub(CacheBackendInterface::class));
    $languageManager->setNegotiator($negotiator);
    // Initialize the negotiated languages.
    $originalLanguage = $languageManager->getCurrentLanguage();
    // Simulate ConfigurableLanguageManager::getLanguageSwitchLinks() running in
    // a fiber in parallel with another process running in a fiber. The second
    // fiber just returns the value of the current language, which should not
    // be from the original language when the second fiber is running,
    // regardless of whether the first fiber suspended while checking access on
    // the link URLs.
    $fibers[] = new \Fiber(fn() => $languageManager->getLanguageSwitchLinks(LanguageInterface::TYPE_INTERFACE, $this->createMock(Url::class)));
    $fibers[] = new \Fiber(fn() => $languageManager->getCurrentLanguage()
      ->getId());
    $return = [];
    // Process fibers until all complete.
    do {
      foreach ($fibers as $key => $fiber) {
        if (!$fiber->isStarted()) {
          $fiber->start();
        }
        elseif ($fiber->isSuspended()) {
          $fiber->resume();
        }
        elseif ($fiber->isTerminated()) {
          $return[$key] = $fiber->getReturn();
          unset($fibers[$key]);
        }
      }
    } while (!empty($fibers));
    // Confirm that the switch links are generated correctly from the first
    // fiber.
    $expectedLinks = [
      'de' => [
        'language' => $languages['de'],
        'url' => $urls['de'],
      ],
      'en' => [
        'language' => $languages['en'],
        'url' => $urls['en'],
      ],
    ];
    $this->assertEquals($expectedLinks, $return[0]->links);
    // Confirm that the original language matches current language when the
    // second fiber ran.
    $this->assertSame($originalLanguage->getId(), $return[1]);
  }

}