diff --git a/tests/Handler/GraphQL/Mutation/HandlerTest.php b/tests/Handler/GraphQL/Mutation/HandlerTest.php
index 3039b78..5096eaf 100644
--- a/tests/Handler/GraphQL/Mutation/HandlerTest.php
+++ b/tests/Handler/GraphQL/Mutation/HandlerTest.php
@@ -12,7 +12,7 @@
 
 class HandlerTest extends SnapshotTestAbstract
 {
-    protected function setUp()
+    protected function setUp(): void
     {
         parent::setUp();
         Injector::inst()->registerService(