test: #3578597 datetime.time service is missing the request stack in kernel tests

      ->normalize($resource_object, 'api_json', ['account' => NULL]);

    $this->assertEquals($baseMaxAge - 500, $resource_normalization->getCacheMaxAge(), 'Max age should be 300 since 500 seconds has passed');

    // Change request time to 800 seconds later, this is the last second the

    // cache backend would return cached data. The max-age at that time should

    // be 0 which is the same as the expire time of the cache entry.

    $current_request->server->set('REQUEST_TIME', $current_request->server->get('REQUEST_TIME') + 800);

    // Change request time to 300 seconds later (800 seconds later in total),

    // this is the last second the cache backend would return cached data. The

    // max-age at that time should be 0 as the request time is the same as the

    // expiration time of the cache entry.

    $current_request->server->set('REQUEST_TIME', $current_request->server->get('REQUEST_TIME') + 300);

    $resource_normalization = $this->serializer

      ->normalize($resource_object, 'api_json', ['account' => NULL]);

    $this->assertEquals(0, $resource_normalization->getCacheMaxAge(), 'Max age should be 0 since max-age has passed');

    // Change request time to 801 seconds later. This validates that max-age

    // never becomes negative. This should never happen as the cache entry

    // is expired at this time and the cache backend would not return data.

    $current_request->server->set('REQUEST_TIME', $current_request->server->get('REQUEST_TIME') + 801);

    // Change request time to 1 second later (801 seconds later in total). This

    // will generate a new cache entry because the one from above has now

    // expired. Thus, the max age of the normalization is back to 800.

    $current_request->server->set('REQUEST_TIME', $current_request->server->get('REQUEST_TIME') + 1);

    $resource_normalization = $this->serializer

      ->normalize($resource_object, 'api_json', ['account' => NULL]);

    $this->assertEquals(0, $resource_normalization->getCacheMaxAge(), 'Max age should be 0 since max-age has passed a second ago');

    $this->assertEquals(800, $resource_normalization->getCacheMaxAge(), 'Max age should be 800 since a new cache item has been created');

  }

    // Keep the container object around for tests.

    $this->container = $container;

    $container

      ->register('datetime.time', 'Drupal\Component\Datetime\Time');

    $container

      ->register('flood', 'Drupal\Core\Flood\MemoryBackend')

      ->addArgument(new Reference('request_stack'));