.../lib/Drupal/Core/Template/ThemeRegistryNodeVisitor.php |  1 +
 .../system/src/Tests/Theme/TwigRegistryLoaderTest.php     | 15 +++++----------
 2 files changed, 6 insertions(+), 10 deletions(-)

diff --git a/core/lib/Drupal/Core/Template/ThemeRegistryNodeVisitor.php b/core/lib/Drupal/Core/Template/ThemeRegistryNodeVisitor.php
index cd1f421..5d8ecab 100644
--- a/core/lib/Drupal/Core/Template/ThemeRegistryNodeVisitor.php
+++ b/core/lib/Drupal/Core/Template/ThemeRegistryNodeVisitor.php
@@ -29,6 +29,7 @@
  * theme's. This matches the behavior outside of Twig.
  *
  * @see https://www.drupal.org/node/2387069
+ * @see http://twig.sensiolabs.org/doc/tags/extends.html#dynamic-inheritance
  *
  * @see twig_render
  */
diff --git a/core/modules/system/src/Tests/Theme/TwigRegistryLoaderTest.php b/core/modules/system/src/Tests/Theme/TwigRegistryLoaderTest.php
index 5cbca9f..86cf7c9 100644
--- a/core/modules/system/src/Tests/Theme/TwigRegistryLoaderTest.php
+++ b/core/modules/system/src/Tests/Theme/TwigRegistryLoaderTest.php
@@ -23,10 +23,12 @@ class TwigRegistryLoaderTest extends WebTestBase {
    */
   protected $twig;
 
+  /**
+   * {@inheritdoc}
+   */
   protected function setUp() {
     parent::setUp();
     \Drupal::service('theme_handler')->install(array('test_theme_twig_registry_loader', 'test_theme_twig_registry_loader_theme', 'test_theme_twig_registry_loader_subtheme'));
-    $this->twig = \Drupal::service('twig');
   }
 
   /**
@@ -36,24 +38,17 @@ public function assertTwigTemplate($value, $message = '', $group = 'Other') {
     $this->assertTrue($value instanceof \Twig_Template, $message, $group);
   }
 
-  /**
-   * Tests template discovery using the Drupal theme registry.
-   */
-  public function testTemplateDiscovery() {
-    $this->assertTwigTemplate($this->twig->resolveTemplate('block.html.twig'), 'Found block.html.twig in block module.');
-  }
-
   /**
    * Tests template extension and includes using the Drupal theme registry.
    */
-  public function testTwigNamespaces() {
+  public function testExtendsAndInclude() {
     // Test the module-provided extend and insert templates.
     $this->drupalGet('twig-theme-test/registry-loader');
     $this->assertText('This line is from twig_theme_test/templates/twig-registry-loader-test-extend.html.twig');
     $this->assertText('This line is from twig_theme_test/templates/twig-registry-loader-test-include.html.twig');
 
     // Enable a theme that overrides the extend and insert templates to ensure
-    // they are picked up by the registry loader.
+    // they are picked up by the registry node visitor.
     $this->config('system.theme')
       ->set('default', 'test_theme_twig_registry_loader')
       ->save();