Issue #3128389 by jungle, cliddell, john.oltman, clayfreeman, acbramley:...

use Drupal\Core\Cache\CacheBackendInterface;

use Drupal\Core\Config\ConfigFactoryInterface;

use Drupal\Core\DependencyInjection\DependencySerializationTrait;

use Drupal\Core\DestructableInterface;

use Drupal\Core\Language\LanguageInterface;

use Drupal\Core\Language\LanguageManagerInterface;

 */

class LocaleTranslation implements TranslatorInterface, DestructableInterface {

  use DependencySerializationTrait;

  /**

   * Storage for strings.

   *

<?php

namespace Drupal\Tests\locale\Kernel;

use Drupal\locale\LocaleTranslation;

use Drupal\KernelTests\KernelTestBase;

/**

 * @coversDefaultClass \Drupal\locale\LocaleTranslation

 * @group locale

 */

class LocaleTranslationTest extends KernelTestBase {

  /**

   * {@inheritdoc}

   */

  protected static $modules = [

    'locale',

  ];

  /**

   * Tests that \Drupal\locale\LocaleTranslation is serializable.

   */

  public function testSerializable() {

    $translation = $this->container->get('string_translator.locale.lookup');

    $this->assertInstanceOf(LocaleTranslation::class, $translation);

    // Prove that serialization and deserialization works without errors.

    $this->assertNotNull($translation);

    $unserialized = unserialize(serialize($translation));

    $this->assertInstanceOf(LocaleTranslation::class, $unserialized);

    // Ensure that all properties on the unserialized object match the original.

    $translation_reflection = new \ReflectionObject($translation);

    $unserialized_reflection = new \ReflectionObject($unserialized);

    // Ignore the '_serviceIds' property in the comparison.

    $properties = array_filter($translation_reflection->getProperties(), function ($value) {

      return $value->getName() !== '_serviceIds';

    });

    foreach ($properties as $value) {

      $value->setAccessible(TRUE);

      $unserialized_property = $unserialized_reflection->getProperty($value->getName());

      $unserialized_property->setAccessible(TRUE);

      $this->assertEquals($unserialized_property->getValue($unserialized), $value->getValue($translation));

    }

  }

}