diff -u b/core/modules/picture/lib/Drupal/picture/Tests/PictureThemeFunctionsTest.php b/core/modules/picture/lib/Drupal/picture/Tests/PictureThemeFunctionsTest.php
--- b/core/modules/picture/lib/Drupal/picture/Tests/PictureThemeFunctionsTest.php
+++ b/core/modules/picture/lib/Drupal/picture/Tests/PictureThemeFunctionsTest.php
@@ -78,7 +78,7 @@
     $style->save();
     $url = $style->buildUrl($original_uri);
 
-    // Test using theme_picture() with a NULL value for the alt option.
+    // Test using theme_picture_formatter() without breakpoints and with a NULL value for the alt option.
     $path = $this->randomName();
     $element = array(
       '#theme' => 'picture_formatter',
@@ -93,7 +93,7 @@
     );
     $rendered_element = render($element);
     $expected_result = '<a href="' . base_path() . $path . '"><img class="image-style-test" src="' . $url . '" /></a>';
-    $this->assertEqual($expected_result, $rendered_element, 'theme_picture_formatter() correctly renders with a NULL value for the alt option.');
+    $this->assertEqual($expected_result, $rendered_element, 'theme_picture_formatter() correctly renders without breakpoints and with a NULL value for the alt option.');
 
     // Test using theme_picture_formatter() without an image title, alt text, or
     // link options.