diff --git a/core/modules/serialization/tests/src/Kernel/EntitySerializationTest.php b/core/modules/serialization/tests/src/Kernel/EntitySerializationTest.php
index a71af15..18c652e 100644
--- a/core/modules/serialization/tests/src/Kernel/EntitySerializationTest.php
+++ b/core/modules/serialization/tests/src/Kernel/EntitySerializationTest.php
@@ -110,7 +110,8 @@ public function testNormalize() {
       ),
       'user_id' => array(
         array(
-          'target_id' => $this->user->id(),
+          // id() will return the string value as it comes from the database.
+          'target_id' => (int) $this->user->id(),
           'target_type' => $this->user->getEntityTypeId(),
           'target_uuid' => $this->user->uuid(),
           'url' => $this->user->url(),