ConfigurableLanguageValidationTest.php

<?php

declare (strict_types=1);
namespace Drupal\Tests\language\Kernel;

use Drupal\KernelTests\Core\Config\ConfigEntityValidationTestBase;
use Drupal\language\Entity\ConfigurableLanguage;

/**
 * Tests validation of configurable_language entities.
 *
 * @group language
 */
class ConfigurableLanguageValidationTest extends ConfigEntityValidationTestBase {
  
  /**
   * {@inheritdoc}
   */
  protected static $modules = [
    'language',
  ];
  
  /**
   * {@inheritdoc}
   */
  protected function setUp() : void {
    parent::setUp();
    $this->entity = ConfigurableLanguage::createFromLangcode('fr');
    $this->entity
      ->save();
  }

}