diff --git a/tests/Serializer/ResponseDeserializerTest.php b/tests/Serializer/ResponseDeserializerTest.php
index 690aab4..4be59c3 100644
--- a/tests/Serializer/ResponseDeserializerTest.php
+++ b/tests/Serializer/ResponseDeserializerTest.php
@@ -46,8 +46,8 @@ public function testCleanResponse(): void {
 
         $res = TestResponseDeserializer::cleanResponse($arg);
 
-        $this->assertNotContains("True", $res);
-        $this->assertNotContains("False", $res);
+        $this->assertStringNotContainsString("True", $res);
+        $this->assertStringNotContainsString("False", $res);
     }
 
     /**