--- /dev/null
+<?php
+
+namespace Drupal\early_rendering_controller_test;
+
+use Drupal\Core\Cache\CacheableResponseInterface;
+use Drupal\Core\Cache\CacheableResponseTrait;
+use Symfony\Component\HttpFoundation\Response;
+
+class CacheableTestResponse extends Response implements CacheableResponseInterface {
+
+ use CacheableResponseTrait;
+
+}