diff --git a/core/modules/entity/src/Tests/EntityDisplayTest.php b/core/modules/entity/src/Tests/EntityDisplayTest.php
index f0c8e0c..1fa6341 100644
--- a/core/modules/entity/src/Tests/EntityDisplayTest.php
+++ b/core/modules/entity/src/Tests/EntityDisplayTest.php
@@ -296,7 +296,7 @@ public function testRenameDeleteBundle() {
 
     $expected_dependencies = array(
       'entity' => array('field.instance.node.article_rename.body', 'node.type.article_rename'),
-      'module' => array('text')
+      'module' => array('text', 'user')
     );
     // Check that the display has dependencies on the bundle, fields and the
     // modules that provide the formatters.
diff --git a/core/modules/entity_reference/src/Tests/EntityReferenceIntegrationTest.php b/core/modules/entity_reference/src/Tests/EntityReferenceIntegrationTest.php
index c904b08..bdb45a5 100644
--- a/core/modules/entity_reference/src/Tests/EntityReferenceIntegrationTest.php
+++ b/core/modules/entity_reference/src/Tests/EntityReferenceIntegrationTest.php
@@ -128,9 +128,11 @@ public function testSupportedEntityTypesAndWidgets() {
       // Test all the other widgets supported by the entity reference field.
       // Since we don't know the form structure for these widgets, just test
       // that editing and saving an already created entity works.
+      // Also exclude the special author reference widgets.
+      $exclude = array('entity_reference_autocomplete', 'entity_reference_autocomplete_tags', 'route_based_autocomplete', 'author_autocomplete');
       $entity = current(entity_load_multiple_by_properties($this->entityType, array('name' => $entity_name)));
       $supported_widgets = \Drupal::service('plugin.manager.field.widget')->getOptions('entity_reference');
-      $supported_widget_types = array_diff(array_keys($supported_widgets), array('entity_reference_autocomplete', 'entity_reference_autocomplete_tags'));
+      $supported_widget_types = array_diff(array_keys($supported_widgets), $exclude);
 
       foreach ($supported_widget_types as $widget_type) {
         entity_get_form_display($this->entityType, $this->bundle, 'default')->setComponent($this->fieldName, array(
diff --git a/core/modules/user/src/Plugin/Field/FieldWidget/AuthorAutocompleteWidget.php b/core/modules/user/src/Plugin/Field/FieldWidget/AuthorAutocompleteWidget.php
index 107f0e6..43834df 100644
--- a/core/modules/user/src/Plugin/Field/FieldWidget/AuthorAutocompleteWidget.php
+++ b/core/modules/user/src/Plugin/Field/FieldWidget/AuthorAutocompleteWidget.php
@@ -30,7 +30,7 @@ class AuthorAutocompleteWidget extends RouteBasedAutocompleteWidget {
   public function formElement(FieldItemListInterface $items, $delta, array $element, array &$form, array &$form_state) {
     $element = parent::formElement($items, $delta, $element, $form, $form_state);
 
-    $element['target_id']['#default_value'] = $items[$delta]->entity->isAuthenticated() ? $items[$delta]->entity->getUsername() : '';
+    $element['target_id']['#default_value'] = $items[$delta]->entity && $items[$delta]->entity->isAuthenticated() ? $items[$delta]->entity->getUsername() : '';
 
     $user_config = \Drupal::config('user.settings');
     $element['target_id']['#description'] = $this->t('Leave blank for %anonymous.', array('%anonymous' => $user_config->get('anonymous')));