Update to Drupal 8.0.2. For more information, see https://www.drupal.org/drupal-8.0.2-release-notes

core/lib/Drupal/Core/Extension/ExtensionDiscovery.php

@@ -15,6 +15,13 @@ use Symfony\Component\HttpFoundation\Request;
 
 /**
  * Discovers available extensions in the filesystem.
+ *
+ * To also discover test modules, add
+ * @code
+ * $settings['extension_discovery_scan_tests'] = TRUE;
+ * @encode
+ * to your settings.php.
+ *
  */
 class ExtensionDiscovery {
 
@@ -134,6 +141,12 @@ class ExtensionDiscovery {
    * - the site-wide directory; i.e., /
    * - the site-specific directory; e.g., /sites/example.com
    *
+   * To also find test modules, add
+   * @code
+   * $settings['extension_discovery_scan_tests'] = TRUE;
+   * @encode
+   * to your settings.php.
+   *
    * The information is returned in an associative array, keyed by the extension
    * name (without .info.yml extension). Extensions found later in the search
    * will take precedence over extensions found earlier - unless they are not

core/lib/Drupal/Core/Extension/ModuleInstallerInterface.php

@@ -23,6 +23,12 @@ interface ModuleInstallerInterface {
    *   - Invoke hook_install() and add it to the list of installed modules.
    * - Invoke hook_modules_installed().
    *
+   * To install test modules add
+   * @code
+   * $settings['extension_discovery_scan_tests'] = TRUE;
+   * @encode
+   * to your settings.php.
+   *
    * @param string[] $module_list
    *   An array of module names.
    * @param bool $enable_dependencies

core/lib/Drupal/Core/Extension/ThemeHandler.php

@@ -19,9 +19,12 @@ class ThemeHandler implements ThemeHandlerInterface {
    * Contains the features enabled for themes by default.
    *
    * @var array
+   *
+   * @see _system_default_theme_features()
    */
   protected $defaultFeatures = array(
     'favicon',
+    'logo',
     'node_user_picture',
     'comment_user_picture',
     'comment_user_verification',