diff --git a/core/lib/Drupal/Core/Config/InstallStorage.php b/core/lib/Drupal/Core/Config/InstallStorage.php
index 5667b29..a6a9d45 100644
--- a/core/lib/Drupal/Core/Config/InstallStorage.php
+++ b/core/lib/Drupal/Core/Config/InstallStorage.php
@@ -114,7 +114,7 @@ protected function getAllFolders() {
       $this->folders = array($profile => drupal_get_path('profile', $profile));
       $folders = drupal_system_listing('/^' . DRUPAL_PHP_FUNCTION_PATTERN . '\.module$/', 'modules');
       $folders += drupal_system_listing('/^' . DRUPAL_PHP_FUNCTION_PATTERN . '\.info\.yml$/', 'themes');
-      $this->folders = array_map(function ($file) {
+      $this->folders += array_map(function ($file) {
         return dirname($file->uri);
       }, $folders);
     }
diff --git a/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php
index d44064e..40a0030 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php
@@ -226,6 +226,8 @@ public function containerBuild(ContainerBuilder $container) {
 
     $container
       ->register('config.storage', 'Drupal\Core\Config\FileStorage')
+      ->addArgument('')
+      ->addArgument(new Reference('serialization.yaml'))
       ->addArgument($this->configDirectories[CONFIG_ACTIVE_DIRECTORY]);
 
     $this->settingsSet('keyvalue_default', 'keyvalue.memory');
diff --git a/core/modules/views/lib/Drupal/views/Tests/ViewTestData.php b/core/modules/views/lib/Drupal/views/Tests/ViewTestData.php
index 1117bd8..5f2f23a 100644
--- a/core/modules/views/lib/Drupal/views/Tests/ViewTestData.php
+++ b/core/modules/views/lib/Drupal/views/Tests/ViewTestData.php
@@ -8,6 +8,7 @@
 namespace Drupal\views\Tests;
 
 use Drupal\Core\Config\FileStorage;
+use Drupal\Core\Serialization\Yaml;
 
 /**
  * Provides tests view data and the base test schema with sample data records.
@@ -44,7 +45,7 @@ public static function createTestViews($class, array $modules) {
           continue;
         }
 
-        $file_storage = new FileStorage($config_dir);
+        $file_storage = new FileStorage('', new Yaml(), $config_dir);
         foreach ($file_storage->listAll('views.view.') as $config_name) {
           $id = str_replace('views.view.', '', $config_name);
           if (in_array($id, $views)) {