diff --git a/core/modules/rest/src/Entity/RestEndpoint.php b/core/modules/rest/src/Entity/RestEndpoint.php
index 28d3c16..ae4a4ac 100644
--- a/core/modules/rest/src/Entity/RestEndpoint.php
+++ b/core/modules/rest/src/Entity/RestEndpoint.php
@@ -34,6 +34,13 @@ class RestEndpoint extends ConfigEntityBase implements RestEndpointInterface {
    */
   protected $configuration;
 
+  /**
+   * {@inheritdoc}
+   */
+  public function id() {
+    return isset($this->plugin_id) ? $this->plugin_id : NULL;
+  }
+
   protected function getLabelFromPlugin() {
     $plugin_definition = \Drupal::service('plugin.manager.rest')
       ->getDefinition(['id' => $this->plugin_id]);
@@ -48,9 +55,9 @@ public function getSettings() {
   }
 
   /**
-   * @param array $settings
+   * {@inheritdoc}
    */
-  public function setSettings($settings) {
+  public function setSettings(array $settings) {
     $this->configuration = $settings;
   }
 
diff --git a/core/modules/rest/src/RestEndpointInterface.php b/core/modules/rest/src/RestEndpointInterface.php
index cf03733..eb141d6 100644
--- a/core/modules/rest/src/RestEndpointInterface.php
+++ b/core/modules/rest/src/RestEndpointInterface.php
@@ -13,5 +13,5 @@ public function getSettings();
   /**
    * @param array $settings
    */
-  public function setSettings($settings);
+  public function setSettings(array $settings);
 }
diff --git a/core/modules/rest/src/Tests/UpdateTest.php b/core/modules/rest/src/Tests/UpdateTest.php
index 599c78b..23cf9fe 100644
--- a/core/modules/rest/src/Tests/UpdateTest.php
+++ b/core/modules/rest/src/Tests/UpdateTest.php
@@ -32,7 +32,7 @@ public function testPatchUpdate() {
     // @todo Test all other entity types here as well.
     $entity_type = 'entity_test';
 
-    $this->enableService('entity:' . $entity_type, 'PATCH');
+    $this->enableService('entity__' . $entity_type, 'PATCH');
     // Create a user account that has the required permissions to create
     // resources via the REST API.
     $permissions = $this->entityPermissions($entity_type, 'update');