diff --git a/tests/phpunit/utils/UtilsTest.php b/tests/phpunit/utils/UtilsTest.php
index b020c682d..a1a64dd57 100644
--- a/tests/phpunit/utils/UtilsTest.php
+++ b/tests/phpunit/utils/UtilsTest.php
@@ -65,6 +65,6 @@ class UtilsTest extends TestCase{
 
 	public function testNamespacedNiceClosureName() : void{
 		//be careful with this test. The closure has to be declared on the same line as the assertion.
-		self::assertSame('closure@' . Utils::cleanPath(__FILE__) . '#L' . __LINE__, Utils::getNiceClosureName(function(){}));
+		self::assertSame('closure@' . Utils::cleanPath(__FILE__) . '#L' . __LINE__, Utils::getNiceClosureName(function() : void{}));
 	}
 }