diff --git a/tests/Doctrine/Tests/DBAL/Functional/Schema/SchemaManagerFunctionalTestCase.php b/tests/Doctrine/Tests/DBAL/Functional/Schema/SchemaManagerFunctionalTestCase.php
index 7b76f802612..80adb98005b 100644
--- a/tests/Doctrine/Tests/DBAL/Functional/Schema/SchemaManagerFunctionalTestCase.php
+++ b/tests/Doctrine/Tests/DBAL/Functional/Schema/SchemaManagerFunctionalTestCase.php
@@ -58,7 +58,7 @@ protected function getPlatformName() : string
         $e         = explode('\\', $class);
         $testClass = end($e);
 
-        return strtolower(str_replace('SchemaManagerTest', null, $testClass));
+        return strtolower(str_replace('SchemaManagerTest', '', $testClass));
     }
 
     protected function setUp() : void