diff --git a/core/modules/node/lib/Drupal/node/Tests/SummaryLengthTest.php b/core/modules/node/lib/Drupal/node/Tests/SummaryLengthTest.php
index 95e64f0..4276146 100644
--- a/core/modules/node/lib/Drupal/node/Tests/SummaryLengthTest.php
+++ b/core/modules/node/lib/Drupal/node/Tests/SummaryLengthTest.php
@@ -37,6 +37,7 @@ function testSummaryLength() {
 
     // Render the node as a teaser.
     $content = entity_render_controller('node')->view($node, 'teaser');
+    $this->assertTrue(strlen($content['body'][0]['#markup']) < 600, 'Teaser is less than 600 characters long.');
     $this->drupalSetContent(drupal_render($content));
     // The string 'What is a Drupalism?' is between the 200th and 600th
     // characters of the node body, so it should be included if the summary is
@@ -52,6 +53,7 @@ function testSummaryLength() {
     // Render the node as a teaser again and check that the summary is now only
     // 200 characters in length and so does not include 'What is a Drupalism?'.
     $content = entity_render_controller('node')->view($node, 'teaser');
+    $this->assertTrue(strlen($content['body'][0]['#markup']) < 200, 'Teaser is less than 200 characters long.');
     $this->drupalSetContent(drupal_render($content));
     $this->assertText($node->label());
     $this->assertNoRaw($expected);