Issue #2430379 by quietone, znerol, larowlan: Add explicit test for session...

<?php

namespace Drupal\Tests\language\Functional;

use Drupal\Core\Language\LanguageInterface;

use Drupal\language\Entity\ConfigurableLanguage;

use Drupal\language\Plugin\LanguageNegotiation\LanguageNegotiationBrowser;

use Drupal\language\Plugin\LanguageNegotiation\LanguageNegotiationSelected;

use Drupal\language\Plugin\LanguageNegotiation\LanguageNegotiationSession;

use Drupal\language\Plugin\LanguageNegotiation\LanguageNegotiationUrl;

use Drupal\Tests\BrowserTestBase;

/**

 * Tests the session language negotiation method.

 *

 * @group language

 */

class LanguageNegotiationSessionTest extends BrowserTestBase {

  /**

   * An administrative user to configure the test environment.

   *

   * @var \Drupal\user\Entity\User

   */

  protected $adminUser;

  /**

   * {@inheritdoc}

   */

  protected static $modules = ['language'];

  /**

   * {@inheritdoc}

   */

  protected $defaultTheme = 'stark';

  /**

   * {@inheritdoc}

   */

  protected function setUp(): void {

    parent::setUp();

    // Create a new user with permission to manage the languages.

    $this->adminUser = $this->drupalCreateUser(['administer languages']);

    $this->drupalLogin($this->adminUser);

    ConfigurableLanguage::createFromLangcode('fr')->save();

  }

  /**

   * Tests language negotiation via query/session parameters.

   */

  public function testSessionLanguageNegotiationMethod() {

    $this->drupalGet('admin/config/regional/language/detection');

    // Enable Session and Selected language for interface language detection.

    $config = $this->config('language.types');

    $config->set('configurable', [LanguageInterface::TYPE_INTERFACE]);

    $config->set('negotiation.language_interface.enabled', [

      LanguageNegotiationSession::METHOD_ID => -6,

      LanguageNegotiationSelected::METHOD_ID => 12,

    ]);

    $config->set('negotiation.language_interface.method_weights', [

      'language-user-admin' => -10,

      LanguageNegotiationUrl::METHOD_ID => -8,

      LanguageNegotiationSession::METHOD_ID => -6,

      'language-user' => -4,

      LanguageNegotiationBrowser::METHOD_ID => -2,

      LanguageNegotiationSelected::METHOD_ID => 12,

    ]);

    $config->save();

    // Set language via query parameter.

    $this->drupalGet('user/' . $this->adminUser->id(), ['query' => ['language' => 'fr']]);

    $this->assertSession()->statusCodeEquals(200);

    $this->assertSession()->responseHeaderEquals('Content-language', 'fr');

    // Verify that the language is persisted in the session.

    $this->drupalGet('user/' . $this->adminUser->id());

    $this->assertSession()->statusCodeEquals(200);

    $this->assertSession()->responseHeaderEquals('Content-language', 'fr');

    // Set language via query parameter.

    $this->drupalGet('user/' . $this->adminUser->id(), ['query' => ['language' => 'en']]);

    $this->assertSession()->statusCodeEquals(200);

    $this->assertSession()->responseHeaderEquals('Content-language', 'en');

    // Verify that the language is persisted in the session.

    $this->drupalGet('admin/config/regional/language');

    $this->assertSession()->statusCodeEquals(200);

    $this->assertSession()->responseHeaderEquals('Content-language', 'en');

  }

}