diff --git a/core/modules/system/lib/Drupal/system/Tests/Common/DiffArrayUnitTest.php b/core/modules/system/lib/Drupal/system/Tests/Common/DiffArrayUnitTest.php
index a12beb9..dffe30a 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Common/DiffArrayUnitTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Common/DiffArrayUnitTest.php
@@ -78,7 +78,7 @@ public function testDiffAssocRecursive() {
     $expected = array(
       'different' => 'no',
       'int_diff' => 1,
-      // The 'array' key should no be returned as it's the same.
+      // The 'array' key should not be returned, as it's the same.
       'array_diff' => array('same' => 'same'),
       'new' => 'new',
     );