diff -u b/core/modules/node/node.tokens.inc b/core/modules/node/node.tokens.inc
--- b/core/modules/node/node.tokens.inc
+++ b/core/modules/node/node.tokens.inc
@@ -154,7 +154,7 @@
 
                 // Cast to string, because "processed" returns a
                 // \Drupal\Component\Render\MarkupInterface via check_markup()
-                // and all unicode utilities expects string input.
+                // and all unicode utilities expect string input.
                 $output = text_summary((string) $output, $item->format, $length);
               }
             }
diff -u b/core/modules/node/tests/src/Kernel/NodeTokenReplaceTest.php b/core/modules/node/tests/src/Kernel/NodeTokenReplaceTest.php
--- b/core/modules/node/tests/src/Kernel/NodeTokenReplaceTest.php
+++ b/core/modules/node/tests/src/Kernel/NodeTokenReplaceTest.php
@@ -120,7 +120,8 @@
    * Tests the [node:summary] token.
    */
   public function testNodeSummaryTokenReplacement() {
-    // Create a node.
+    // Length of this text is 828 characters and it's longer than a default
+    // trim length setting (600).
     $text = 'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Morbi diam dui, finibus et purus ac, elementum pretium augue. '
         . 'Fusce lacus nisl, feugiat sit amet blandit sed, mattis eu ligula. Duis laoreet dui non felis maximus fringilla. '
         . 'Maecenas tempor magna id urna dapibus, in elementum mauris consequat. '
@@ -130,7 +131,8 @@
         . 'Aenean sit amet finibus turpis. Donec viverra vel eros eget varius. Praesent rutrum est diam. '
         . 'Mauris at odio scelerisque, mattis mi et, tempor eros. '
         . 'Vestibulum sollicitudin sem quis diam sollicitudin posuere. Nam finibus vestibulum suscipit. '
-        . 'Fusce tempor tincidunt lorem vitae mollis.'; // 828
+        . 'Fusce tempor tincidunt lorem vitae mollis.';
+    // Create a node.
     /* @var $node \Drupal\node\NodeInterface */
     $node = Node::create([
       'type' => 'article',