diff --git a/Tests/Normalizer/ObjectNormalizerTest.php b/Tests/Normalizer/ObjectNormalizerTest.php
index 36957ac5..9e4c76d9 100644
--- a/Tests/Normalizer/ObjectNormalizerTest.php
+++ b/Tests/Normalizer/ObjectNormalizerTest.php
@@ -1043,6 +1043,11 @@ public function __get($name)
             return $this->foo = 123;
         }
     }
+
+    public function __isset($name)
+    {
+        return 'foo' === $name;
+    }
 }
 
 class FormatAndContextAwareNormalizer extends ObjectNormalizer