diff --git a/core/modules/system/lib/Drupal/system/Tests/Common/AttributesUnitTest.php b/core/modules/system/lib/Drupal/system/Tests/Common/AttributesUnitTest.php
index 7b5305d..c28f675 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Common/AttributesUnitTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Common/AttributesUnitTest.php
@@ -27,6 +27,7 @@ public static function getInfo() {
    */
   function testDrupalAttributes() {
     // Verify that special characters are HTML encoded.
+    $this->assertIdentical((string) new Attribute(array('&"\'<>' => 'value')), ' &amp;&quot;&#039;&lt;&gt;="value"', 'HTML encode attribute names.');
     $this->assertIdentical((string) new Attribute(array('title' => '&"\'<>')), ' title="&amp;&quot;&#039;&lt;&gt;"', 'HTML encode attribute values.');
 
     // Verify multi-value attributes are concatenated with spaces.
@@ -37,6 +38,10 @@ function testDrupalAttributes() {
     $this->assertIdentical((string) new Attribute(array('alt' => '')), ' alt=""', 'Empty attribute value #1.');
     $this->assertIdentical((string) new Attribute(array('alt' => NULL)), ' alt=""', 'Empty attribute value #2.');
 
+    // Verify boolean attribute values are rendered correctly.
+    $this->assertIdentical((string) new Attribute(array('disabled' => TRUE)), ' disabled', 'Boolean attribute is rendered.');
+    $this->assertIdentical((string) new Attribute(array('disabled' => FALSE)), '', 'Boolean attribute is not rendered.');
+
     // Verify multiple attributes are rendered.
     $attributes = array(
       'id' => 'id-test',