diff --git a/core/modules/system/src/Tests/Theme/FastTest.php b/core/modules/system/src/Tests/Theme/FastTest.php
index a05666f..cf773d5 100644
--- a/core/modules/system/src/Tests/Theme/FastTest.php
+++ b/core/modules/system/src/Tests/Theme/FastTest.php
@@ -29,6 +29,7 @@ protected function setUp() {
   function testUserAutocomplete() {
     $this->drupalLogin($this->account);
     $this->drupalGet('user/autocomplete', array('query' => array('q' => $this->account->getUsername())));
+    $this->assertResponse(200);
     $this->assertRaw($this->account->getUsername());
     $this->assertNoText('registry initialized', 'The registry was not initialized');
   }