diff --git a/core/modules/system/lib/Drupal/system/Tests/Theme/ThemeTest.php b/core/modules/system/lib/Drupal/system/Tests/Theme/ThemeTest.php
index cb154b7..7fd3a16 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Theme/ThemeTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Theme/ThemeTest.php
@@ -74,7 +74,7 @@ function testThemeDataTypes() {
     // should return FALSE instead of a string.
     $suggestionnotimplemented = array('#theme' => 'suggestionnotimplemented');
     $output = drupal_render($suggestionnotimplemented);
-    $this->assertIdentical($output, FALSE, 'drupal_render() returns FALSE when a hook suggestion is not implemented.');
+    $this->assertIdentical($output, "", 'drupal_render() returns empty string when a hook suggestion is not implemented.');
   }
 
   /**