diff --git a/core/modules/page_cache/src/Tests/PageCacheTest.php b/core/modules/page_cache/src/Tests/PageCacheTest.php
index bcf51fe..e76bc1d 100644
--- a/core/modules/page_cache/src/Tests/PageCacheTest.php
+++ b/core/modules/page_cache/src/Tests/PageCacheTest.php
@@ -206,7 +206,7 @@ public function testFormImmutability() {
 
     $verify_immutable_flag = function ($request_method, $immutable_flag_exists) {
       // Mock a request.
-      $request = Request::create('/');
+      $request = Request::create($this->buildUrl(''));
       $request->setMethod($request_method);
       $this->container->get('request_stack')->push($request);