diff --git a/core/modules/system/lib/Drupal/system/Tests/Bootstrap/PageCacheTest.php b/core/modules/system/lib/Drupal/system/Tests/Bootstrap/PageCacheTest.php
index aec3355..3884644 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Bootstrap/PageCacheTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Bootstrap/PageCacheTest.php
@@ -134,7 +134,7 @@ function testConditionalRequests() {
     $this->drupalLogin($user);
     $this->drupalGet('', array(), array('If-Modified-Since: ' . $last_modified, 'If-None-Match: ' . $etag));
     $this->assertResponse(200, 'Conditional request returned 200 OK for authenticated user.');
-    $this->assertFalse($this->drupalGetHeader('X-Drupal-Cache'), 'Absense of Page was not cached.');
+    $this->assertFalse($this->drupalGetHeader('X-Drupal-Cache'), 'Absence of Page was not cached.');
   }
 
   /**