diff --git c/core/modules/system/tests/modules/theme_test/lib/Drupal/theme_test/ThemeTestController.php w/core/modules/system/tests/modules/theme_test/lib/Drupal/theme_test/ThemeTestController.php
index 6dfcc4b..f94e6c5 100644
--- c/core/modules/system/tests/modules/theme_test/lib/Drupal/theme_test/ThemeTestController.php
+++ w/core/modules/system/tests/modules/theme_test/lib/Drupal/theme_test/ThemeTestController.php
@@ -15,7 +15,10 @@
 class ThemeTestController extends ControllerBase {
 
   /**
-   * Menu callback for testing that a theme template overrides a theme function.
+   * A theme template that overrides a theme function.
+   *
+   * @return array
+   *   Render array containing a theme.
    */
   public function functionTemplateOverridden() {
     return array(
@@ -26,10 +29,8 @@ public function functionTemplateOverridden() {
   /**
    * Adds stylesheets to test theme .info.yml property processing.
    *
-   * @see test_basetheme.info.yml
-   * @see test_subtheme.info.yml
-   * @see \Drupal\system\Tests\Theme\ThemeInfoStylesTest
-   * @see http://drupal.org/node/967266#comment-3689670
+   * @return array
+   *   A render array containing custom stylesheets.
    */
   public function testInfoStylesheets() {
     $path = drupal_get_path('module', 'theme_test');
@@ -49,8 +50,11 @@ public function testInfoStylesheets() {
 
   /**
    * Tests template overridding based on filename.
+   *
+   * @return array
+   *   A render array containing a theme override.
    */
-  function testTemplate() {
+  public function testTemplate() {
     return array(
       '#theme' => 'theme_test_template_test',
     );
@@ -58,6 +62,9 @@ function testTemplate() {
 
   /**
    * Calls a theme hook suggestion.
+   *
+   * @return string
+   *   An HTML string containing the themed output.
    */
   public function testSuggestion() {
     return theme(array('theme_test__suggestion', 'theme_test'), array());
@@ -67,6 +74,9 @@ public function testSuggestion() {
  * This is for testing that the theme can have hook_*_alter() implementations
  * that run during page callback execution, even before theme() is called for
  * the first time.
+ *
+ * @return string
+ *   A string containing the altered data.
  */
   public function testAlter() {
     $data = 'foo';
diff --git c/core/modules/system/tests/modules/theme_test/theme_test.module w/core/modules/system/tests/modules/theme_test/theme_test.module
index 4e3361e..8f3445d 100644
--- c/core/modules/system/tests/modules/theme_test/theme_test.module
+++ w/core/modules/system/tests/modules/theme_test/theme_test.module
@@ -52,6 +52,7 @@ function theme_test_menu() {
   );
   $items['theme-test/alter'] = array(
     'theme callback' => '_theme_custom_theme',
+    'route_name' => 'theme_test_alter',
     'type' => MENU_CALLBACK,
   );
   $items['theme-test/request-listener'] = array(
diff --git c/core/modules/system/tests/modules/theme_test/theme_test.routing.yml w/core/modules/system/tests/modules/theme_test/theme_test.routing.yml
index 0d35863..9ff8172 100644
--- c/core/modules/system/tests/modules/theme_test/theme_test.routing.yml
+++ w/core/modules/system/tests/modules/theme_test/theme_test.routing.yml
@@ -20,7 +20,7 @@ theme_test_template_test:
     _access: 'TRUE'
 
 theme_test_suggestion:
-  pattern: 'theme-test/suggestion'
+  pattern: '/theme-test/suggestion'
   defaults:
     _content: '\Drupal\theme_test\ThemeTestController::testSuggestion'
     _title: 'Suggestion'
@@ -28,7 +28,7 @@ theme_test_suggestion:
     _access: 'TRUE'
 
 theme_test_alter:
-  pattern: 'theme-test/alter'
+  pattern: '/theme-test/alter'
   defaults:
     _content: '\Drupal\theme_test\ThemeTestController::testAlter'
     _title: 'Suggestion'