diff --git a/core/tests/Drupal/Tests/Core/StringTranslation/TranslationWrapperTest.php b/core/tests/Drupal/Tests/Core/StringTranslation/TranslationWrapperTest.php
index d07d8031f5..c3b7bcfe99 100644
--- a/core/tests/Drupal/Tests/Core/StringTranslation/TranslationWrapperTest.php
+++ b/core/tests/Drupal/Tests/Core/StringTranslation/TranslationWrapperTest.php
@@ -2,6 +2,7 @@
 
 namespace Drupal\Tests\Core\StringTranslation;
 
+use Drupal\Core\StringTranslation\TranslatableMarkup;
 use Drupal\Core\StringTranslation\TranslationWrapper;
 use Drupal\Tests\UnitTestCase;
 
@@ -19,7 +20,8 @@ class TranslationWrapperTest extends UnitTestCase {
    * @expectedDeprecation Drupal\Core\StringTranslation\TranslationWrapper is deprecated in drupal:8.0.0 and is removed from drupal:10.0.0. Use the \Drupal\Core\StringTranslation\TranslatableMarkup class instead. See https://www.drupal.org/node/2571255
    */
   public function testTranslationWrapper() {
-    new TranslationWrapper('Deprecated');
+    $object = new TranslationWrapper('Deprecated');
+    $this->assertTrue($object instanceof TranslatableMarkup);
   }
 
 }