diff --git a/core/tests/Drupal/Tests/Component/Utility/XssTest.php b/core/tests/Drupal/Tests/Component/Utility/XssTest.php
index 3a090b8..a8c6383 100644
--- a/core/tests/Drupal/Tests/Component/Utility/XssTest.php
+++ b/core/tests/Drupal/Tests/Component/Utility/XssTest.php
@@ -486,6 +486,41 @@ public function testQuestionSign() {
   }
 
   /**
+   * Check that strings in html attributes are are correctly processed.
+   *
+   * @dataProvider providerTestAttributes
+   */
+  public function testAttribute($value, $expected, $message, $allowed_tags = NULL) {
+    if ($allowed_tags === NULL) {
+      $value = Xss::filter($value);
+    }
+    else {
+      $value = Xss::filter($value, $allowed_tags);
+    }
+    $this->assertEquals($expected, $value, $message);
+  }
+
+  /**
+   * Data provider for testFilterXssAdminNotNormalized().
+   */
+  public function providerTestAttributes() {
+    return array(
+      array(
+        '<img src="http://example.com/foo.jpg" title="Example: title" alt="Example: alt">',
+        '<img src="http://example.com/foo.jpg" title="Example: title" alt="Example: alt">',
+        'Image tag with alt and title attribute',
+        array('img')
+      ),
+      array(
+        '<img src="http://example.com/foo.jpg" data-caption="Drupal 8: The best release ever.">',
+        '<img src="http://example.com/foo.jpg" data-caption="Drupal 8: The best release ever.">',
+        'Image tag with alt and title attribute',
+        array('img')
+      ),
+    );
+  }
+
+  /**
    * Checks that \Drupal\Component\Utility\Xss::filterAdmin() correctly strips unallowed tags.
    */
   public function testFilterXSSAdmin() {