diff --git a/core/modules/system/src/Tests/Theme/FastTest.php b/core/modules/system/src/Tests/Theme/FastTest.php
index 4c19650..5743d28 100644
--- a/core/modules/system/src/Tests/Theme/FastTest.php
+++ b/core/modules/system/src/Tests/Theme/FastTest.php
@@ -34,7 +34,7 @@ protected function setUp() {
   function testUserAutocomplete() {
     $this->drupalLogin($this->account);
     $this->drupalGet('user/autocomplete', array('query' => array('q' => $this->account->getUsername())));
-    $this->assertRaw($this->account->getUsername());
+    $this->assertRaw(json_encode($this->account->getUsername(), JSON_HEX_APOS));
     $this->assertNoText('registry initialized', 'The registry was not initialized');
   }
 }