UserLanguageTest.php

<?php

namespace Drupal\Tests\user\Functional;

use Drupal\Core\Language\LanguageInterface;
use Drupal\Tests\BrowserTestBase;

/**
 * Functional tests for a user's ability to change their default language.
 *
 * @group user
 */
class UserLanguageTest extends BrowserTestBase {
    
    /**
     * Modules to enable.
     *
     * @var array
     */
    public static $modules = [
        'user',
        'language',
    ];
    
    /**
     * {@inheritdoc}
     */
    protected $defaultTheme = 'stark';
    
    /**
     * Test if user can change their default language.
     */
    public function testUserLanguageConfiguration() {
        // User to add and remove language.
        $admin_user = $this->drupalCreateUser([
            'administer languages',
            'access administration pages',
        ]);
        // User to change their default language.
        $web_user = $this->drupalCreateUser();
        // Add custom language.
        $this->drupalLogin($admin_user);
        // Code for the language.
        $langcode = 'xx';
        // The English name for the language.
        $name = $this->randomMachineName(16);
        $edit = [
            'predefined_langcode' => 'custom',
            'langcode' => $langcode,
            'label' => $name,
            'direction' => LanguageInterface::DIRECTION_LTR,
        ];
        $this->drupalPostForm('admin/config/regional/language/add', $edit, t('Add custom language'));
        $this->drupalLogout();
        // Log in as normal user and edit account settings.
        $this->drupalLogin($web_user);
        $path = 'user/' . $web_user->id() . '/edit';
        $this->drupalGet($path);
        // Ensure language settings widget is available.
        $this->assertText(t('Language'), 'Language selector available.');
        // Ensure custom language is present.
        $this->assertText($name, 'Language present on form.');
        // Switch to our custom language.
        $edit = [
            'preferred_langcode' => $langcode,
        ];
        $this->drupalPostForm($path, $edit, t('Save'));
        // Ensure form was submitted successfully.
        $this->assertText(t('The changes have been saved.'), 'Changes were saved.');
        // Check if language was changed.
        $this->assertOptionSelected('edit-preferred-langcode', $langcode, 'Default language successfully updated.');
        $this->drupalLogout();
    }

}