diff --git a/core/tests/Drupal/Tests/Core/Form/FormAlterTest.php b/core/tests/Drupal/Tests/Core/Form/FormAlterTest.php
index 5e61445..05bafdd 100644
--- a/core/tests/Drupal/Tests/Core/Form/FormAlterTest.php
+++ b/core/tests/Drupal/Tests/Core/Form/FormAlterTest.php
@@ -56,7 +56,7 @@ protected function setUp() {
    */
   public function testAlterForm($form_id, $expected_hooks, $form_state_additions = []) {
     $form = [];
-    $form_state = new FormState($form_state_additions);
+    $form_state = (new FormState())->setFormState($form_state_additions);
 
     $this->moduleHandler->expects($this->once())
       ->method('alter')