diff -ru src/Symfony/Component/ObjectMapper/Tests/MapCollectionTest.php src/Symfony/Component/ObjectMapper/Tests/MapCollectionTest.php
--- src/Symfony/Component/ObjectMapper/Tests/MapCollectionTest.php	2025-05-16 08:18:15.814351408 +0000
+++ src/Symfony/Component/ObjectMapper/Tests/MapCollectionTest.php	2025-05-16 08:18:17.212354280 +0000
@@ -19,7 +19,7 @@
 
 class ObjectMapperCollectionTreeTest extends TestCase
 {
-    public function testMapCollectionOfObjects(): void
+    public function testMapCollectionOfObjects()
     {
         $mapper = new ObjectMapper();
         $source = new SourceWithCollection([
@@ -37,7 +37,7 @@
         $this->assertEquals('B', $result->items[1]->label);
     }
 
-    public function testMapTreeStructure(): void
+    public function testMapTreeStructure()
     {
         $source = new SourceNode('Root', [
             new SourceNode('Child 1'),