only in patch2:
unchanged:
--- a/core/modules/system/src/Tests/Entity/EntityAutocompleteTest.php
+++ b/core/modules/system/src/Tests/Entity/EntityAutocompleteTest.php
@@ -11,6 +11,7 @@
 use Drupal\Component\Utility\Crypt;
 use Drupal\Component\Utility\Html;
 use Drupal\Component\Utility\Tags;
+use Drupal\Core\Entity\Element\EntityAutocomplete;
 use Drupal\Core\Site\Settings;
 use Drupal\system\Controller\EntityAutocompleteController;
 use Symfony\Component\HttpFoundation\Request;
@@ -98,6 +99,30 @@ function testEntityReferenceAutocompletion() {
   }
 
   /**
+   * Tests that entity IDs can be extracted from autocomplete strings.
+   */
+  protected function testExtractEntityIdFromAutocompleteInput() {
+    $result = EntityAutocomplete::extractEntityIdFromAutocompleteInput('Name (42)');
+    $this->assertEqual('42', $result);
+    $result = EntityAutocomplete::extractEntityIdFromAutocompleteInput('Name (entity_id)');
+    $this->assertEqual('entity_id', $result);
+    $result = EntityAutocomplete::extractEntityIdFromAutocompleteInput('Name');
+    $this->assertNull($result);
+  }
+
+  /**
+   * Tests that entity labels can be extracted from autocomplete strings.
+   */
+  protected function testExtractEntityLabelFromAutocompleteInput() {
+    $result = EntityAutocomplete::extractEntityLabelFromAutocompleteInput('Name (42)');
+    $this->assertEqual('Name', $result);
+    $result = EntityAutocomplete::extractEntityLabelFromAutocompleteInput('Name (entity_id)');
+    $this->assertEqual('Name', $result);
+    $result = EntityAutocomplete::extractEntityLabelFromAutocompleteInput('Name');
+    $this->assertNull($result);
+  }
+
+  /**
    * Tests that missing or invalid selection setting key are handled correctly.
    */
   public function testSelectionSettingsHandling() {