diff --git a/core/includes/common.inc b/core/includes/common.inc
index 95ec2e2..5f8f1b8 100644
--- a/core/includes/common.inc
+++ b/core/includes/common.inc
@@ -1366,7 +1366,7 @@ function drupal_clear_css_cache() {
  * @return
  *   The cleaned identifier.
  *
- * @deprecated in Drupal 8.x-dev, will be removed before Drupal 8.0.
+ * @deprecated in Drupal 8.x-dev, will be removed before Drupal 8.0.0.
  *   Use \Drupal\Component\Utility\Html::cleanCssIdentifier()
  */
 function drupal_clean_css_identifier($identifier, $filter = array(' ' => '-', '_' => '-', '__' => '__', '/' => '-', '[' => '-', ']' => '')) {
@@ -1385,7 +1385,7 @@ function drupal_clean_css_identifier($identifier, $filter = array(' ' => '-', '_
  * @return
  *   The cleaned class name.
  *
- * @deprecated in Drupal 8.x-dev, will be removed before Drupal 8.0.
+ * @deprecated in Drupal 8.x-dev, will be removed before Drupal 8.0.0.
  *   Use \Drupal\Component\Utility\Html::getClass()
  */
 function drupal_html_class($class) {
@@ -1419,7 +1419,7 @@ function drupal_html_class($class) {
  * @return
  *   The cleaned ID.
  *
- * @deprecated in Drupal 8.x-dev, will be removed before Drupal 8.0.
+ * @deprecated in Drupal 8.x-dev, will be removed before Drupal 8.0.0.
  *   Use \Drupal\Component\Utility\Html::getUniqueId()
  */
 function drupal_html_id($id) {
@@ -1440,7 +1440,7 @@ function drupal_html_id($id) {
  *
  * @see drupal_html_id()
  *
- * @deprecated in Drupal 8.x-dev, will be removed before Drupal 8.0.
+ * @deprecated in Drupal 8.x-dev, will be removed before Drupal 8.0.0.
  *   Use \Drupal\Component\Utility\Html::getId()
  */
 function drupal_clean_id_identifier($id) {
diff --git a/core/tests/Drupal/Tests/Core/Utility/HtmlTest.php b/core/tests/Drupal/Tests/Core/Utility/HtmlTest.php
index 5ebd0bc..cd78d20 100644
--- a/core/tests/Drupal/Tests/Core/Utility/HtmlTest.php
+++ b/core/tests/Drupal/Tests/Core/Utility/HtmlTest.php
@@ -13,7 +13,7 @@
 /**
  * Tests \Drupal\Component\Utility\Html.
  *
- * @group Drupal
+ * @group Common
  *
  * @coversDefaultClass \Drupal\Component\Utility\Html
  */
@@ -22,12 +22,12 @@ class HtmlTest extends UnitTestCase {
   /**
    * {@inheritdoc}
    */
-  public static function getInfo() {
-    return array(
-      'name' => 'HTML identifiers',
-      'description' => 'Test the methods Html::getClass(), Html::getUniqueId() and Html::cleanCssIdentifier() for expected behavior.',
-      'group' => 'Common',
-    );
+  protected function setUp() {
+    parent::setUp();
+
+    $property = new \ReflectionProperty('Drupal\Component\Utility\Html', 'seenIdsInit');
+    $property->setAccessible(TRUE);
+    $property->setValue(NULL);
   }
 
   /**
@@ -143,6 +143,43 @@ public function providerTestHtmlGetUniqueId() {
    *   The expected result.
    * @param string $source
    *   The string being transformed to an ID.
+   * @param bool $reset
+   *   (optional) If TRUE, reset the list of seen IDs. Defaults to FALSE.
+   *
+   * @dataProvider providerTestHtmlGetUniqueIdWithAjaxIds
+   *
+   * @covers ::getUniqueId
+   */
+  public function testHtmlGetUniqueIdWithAjaxIds($expected, $source, $reset = FALSE) {
+    if ($reset) {
+      Html::resetSeenIds();
+    }
+    Html::setAjaxHtmlIds('test-unique-id1 test-unique-id2--3');
+    $this->assertSame($expected, Html::getUniqueId($source));
+  }
+
+  /**
+   * Provides test data for testHtmlGetId().
+   *
+   * @return array
+   *   Test data.
+   */
+  public function providerTestHtmlGetUniqueIdWithAjaxIds() {
+    return array(
+      array('test-unique-id1--2', 'test-unique-id1', TRUE),
+      array('test-unique-id1--3', 'test-unique-id1'),
+      array('test-unique-id2--4', 'test-unique-id2', TRUE),
+      array('test-unique-id2--5', 'test-unique-id2'),
+    );
+  }
+
+  /**
+   * Tests the Html::getUniqueId() method.
+   *
+   * @param string $expected
+   *   The expected result.
+   * @param string $source
+   *   The string being transformed to an ID.
    *
    * @dataProvider providerTestHtmlGetId
    *