diff --git a/core/tests/Drupal/FunctionalJavascriptTests/Core/Field/Widget/MachineNameWidgetTest.php b/core/tests/Drupal/FunctionalJavascriptTests/Core/Field/Widget/MachineNameWidgetTest.php
index c5fbc65c55..91b930213c 100644
--- a/core/tests/Drupal/FunctionalJavascriptTests/Core/Field/Widget/MachineNameWidgetTest.php
+++ b/core/tests/Drupal/FunctionalJavascriptTests/Core/Field/Widget/MachineNameWidgetTest.php
@@ -25,7 +25,7 @@ class MachineNameWidgetTest extends WebDriverTestBase {
   /**
    * {@inheritdoc}
    */
-  protected function setUp() {
+  protected function setUp(): void {
     parent::setUp();
 
     // Create a web user.