diff --git a/tests/Node/Expression/FilterTest.php b/tests/Node/Expression/FilterTest.php
index af26a5cb4..2da04c901 100644
--- a/tests/Node/Expression/FilterTest.php
+++ b/tests/Node/Expression/FilterTest.php
@@ -237,7 +237,7 @@ function twig_tests_filter_all(string $charset, Environment $env, array $context
 
 class ChildMagicCallStub extends ParentMagicCallStub
 {
-    public static function identifier()
+    public static function identifier(): string
     {
         return 'child';
     }
@@ -245,7 +245,7 @@ class ChildMagicCallStub extends ParentMagicCallStub
 
 class ParentMagicCallStub
 {
-    public static function identifier(): void
+    public static function identifier(): string
     {
         throw new \Exception('Identifier has not been defined.');
     }