diff --git a/core/includes/config.inc b/core/includes/config.inc
index eb9dcce..8d37e13 100644
--- a/core/includes/config.inc
+++ b/core/includes/config.inc
@@ -43,7 +43,6 @@ function config_install_default_config($module) {
   if (is_dir($module_config_dir)) {
     $database_storage = new DatabaseStorage();
     $module_file_storage = new FileStorage(array('directory' => $module_config_dir));
-    $file_storage = new FileStorage();
 
     $files = glob($module_config_dir . '/*.' . FileStorage::getFileExtension());
     foreach ($files as $key => $file) {
@@ -54,8 +53,6 @@ function config_install_default_config($module) {
 
       $data = $module_file_storage->read($config_name);
       $database_storage->write($config_name, $data);
-      // @todo Only explicit exports are supposed to write to FileStorage.
-      $file_storage->write($config_name, $data);
     }
   }
 }
diff --git a/core/includes/install.inc b/core/includes/install.inc
index 49bc272..67ca802 100644
--- a/core/includes/install.inc
+++ b/core/includes/install.inc
@@ -1,7 +1,7 @@
 <?php
 
 use Drupal\Core\Database\Database;
-use Drupal\Core\Config\FileStorage;
+use Drupal\Core\Config\DatabaseStorage;
 
 /**
  * Indicates that a module has not been installed yet.
@@ -387,24 +387,16 @@ function drupal_uninstall_modules($module_list = array(), $uninstall_dependents
     $module_list = array_keys($module_list);
   }
 
-  $file_storage = new FileStorage();
   foreach ($module_list as $module) {
     // Uninstall the module.
     module_load_install($module);
     module_invoke($module, 'uninstall');
     drupal_uninstall_schema($module);
 
-    // Remove any stray configuration settings.
-    // Get the names of default configurations provided by this module
-    // by scanning its config directory.
-    $module_config_dir = drupal_get_path('module', $module) . '/config';
-    if (is_dir($module_config_dir)) {
-      $files = glob($module_config_dir . '/*.' . FileStorage::getFileExtension());
-      foreach ($files as $file) {
-        $config_name = basename($file, '.' . FileStorage::getFileExtension());
-        // Delete the configuration from storage.
-        $file_storage->delete($config_name);
-      }
+    // Remove all configuration belonging to the module.
+    $config_names = DatabaseStorage::getNamesWithPrefix($module . '.');
+    foreach ($config_names as $config_name) {
+      config($config_name)->delete();
     }
 
     watchdog('system', '%module module uninstalled.', array('%module' => $module), WATCHDOG_INFO);
diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigFileContentTest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigFileContentTest.php
index 36ab251..42fcfb6 100644
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigFileContentTest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigFileContentTest.php
@@ -62,7 +62,7 @@ class ConfigFileContentTest extends WebTestBase {
     $config = config($name);
 
     // Verify an configuration object is returned.
-//    $this->assertEqual($config->name, $name);
+    $this->assertEqual($config->getName(), $name);
     $this->assertTrue($config, t('Config object created.'));
 
     // Verify the configuration object is empty.
diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigFileSecurityTest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigFileSecurityTest.php
deleted file mode 100644
index ae80fb2..0000000
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigFileSecurityTest.php
+++ /dev/null
@@ -1,48 +0,0 @@
-<?php
-
-/**
- * @file
- * Definition of Drupal\config\Tests\ConfigFileSecurityTest.
- */
-
-namespace Drupal\config\Tests;
-
-use Drupal\Core\Config\FileStorage;
-use Drupal\simpletest\WebTestBase;
-
-/**
- * Tests the secure file writer.
- */
-class ConfigFileSecurityTest extends WebTestBase {
-  protected $filename = 'foo.bar';
-
-  protected $testContent = array('greeting' => 'Good morning, Denver!');
-
-  public static function getInfo() {
-    return array(
-      'name' => 'File security',
-      'description' => 'Tests security of saved configuration files.',
-      'group' => 'Configuration',
-    );
-  }
-
-  /**
-   * Tests that a file written by this system can be successfully read back.
-   */
-  function testFilePersist() {
-    $file = new FileStorage();
-    $file->write($this->filename, $this->testContent);
-
-    // Reading should throw an exception in case of bad validation.
-    // Note that if any other exception is thrown, we let the test system
-    // handle catching and reporting it.
-    try {
-      $saved_content = $file->read($this->filename);
-
-      $this->assertEqual($saved_content, $this->testContent);
-    }
-    catch (Exception $e) {
-      $this->fail('File failed verification when being read.');
-    }
-  }
-}
diff --git a/core/modules/system/system.test b/core/modules/system/system.test
index 17b96c8..80cde8b 100644
--- a/core/modules/system/system.test
+++ b/core/modules/system/system.test
@@ -1,6 +1,7 @@
 <?php
 
 use Drupal\Core\Database\Database;
+use Drupal\Core\Config\DatabaseStorage;
 use Drupal\Core\Config\FileStorage;
 use Drupal\Component\Graph\Graph;
 use Drupal\simpletest\WebTestBase;
@@ -77,65 +78,49 @@ class ModuleTestCase extends WebTestBase {
   }
 
   /**
-   * Assert that a module's config files have been loaded.
+   * Asserts that the default configuration of a module has been installed.
    *
    * @param string $module
    *   The name of the module.
    *
    * @return bool
-   *   TRUE if the module's config files exist, FALSE otherwise.
+   *   TRUE if configuration has been installed, FALSE otherwise.
    */
-  function assertModuleConfigFilesExist($module) {
-    // Define test variable.
-    $files_exist = TRUE;
-    // Get the path to the module's config dir.
+  function assertModuleConfig($module) {
     $module_config_dir = drupal_get_path('module', $module) . '/config';
-    if (is_dir($module_config_dir)) {
-      $files = glob($module_config_dir . '/*.' . FileStorage::getFileExtension());
-      $this->assertTrue($files);
-      $config_dir = config_get_config_directory();
-      // Get the filename of each config file.
-      foreach ($files as $file) {
-        $parts = explode('/', $file);
-        $filename = array_pop($parts);
-        if (!file_exists($config_dir . '/' . $filename)) {
-          $files_exist = FALSE;
-        }
-      }
+    if (!is_dir($module_config_dir)) {
+      return;
     }
+    $files = glob($module_config_dir . '/*.' . FileStorage::getFileExtension());
+
+    // Verify that the config directory is not empty.
+    $this->assertTrue($files);
 
-    return $this->assertTrue($files_exist, t('All config files defined by the @module module have been copied to the live config directory.', array('@module' => $module)));
+    // Check whether each default configuration object exists in the active
+    // store, and if so, remove it from the stack.
+    foreach ($files as $key => $file) {
+      $name = basename($file, '.' . FileStorage::getFileExtension());
+      if (config($name)->get()) {
+        unset($files[$key]);
+      }
+    }
+    // Verify that all configuration has been installed (which means that $files
+    // is empty).
+    return $this->assertFalse($files, format_string('Default configuration of @module module found.', array('@module' => $module)));
   }
 
   /**
-   * Assert that none of a module's default config files are loaded.
+   * Asserts that no configuration exists for a given module.
    *
    * @param string $module
    *   The name of the module.
    *
    * @return bool
-   *   TRUE if the module's config files do not exist, FALSE otherwise.
+   *   TRUE if no configuration was found, FALSE otherwise.
    */
-  function assertModuleConfigFilesDoNotExist($module) {
-    // Define test variable.
-    $files_exist = FALSE;
-    // Get the path to the module's config dir.
-    $module_config_dir = drupal_get_path('module', $module) . '/config';
-    if (is_dir($module_config_dir)) {
-      $files = glob($module_config_dir . '/*.' . FileStorage::getFileExtension());
-      $this->assertTrue($files);
-      $config_dir = config_get_config_directory();
-      // Get the filename of each config file.
-      foreach ($files as $file) {
-        $parts = explode('/', $file);
-        $filename = array_pop($parts);
-        if (file_exists($config_dir . '/' . $filename)) {
-          $files_exist = TRUE;
-        }
-      }
-    }
-
-    return $this->assertFalse($files_exist, t('All config files defined by the @module module have been deleted from the live config directory.', array('@module' => $module)));
+  function assertNoModuleConfig($module) {
+    $names = DatabaseStorage::getNamesWithPrefix($module . '.');
+    return $this->assertFalse($names, format_string('No configuration found for @module module.', array('@module' => $module)));
   }
 
   /**
@@ -293,7 +278,7 @@ class EnableDisableTestCase extends ModuleTestCase {
           $this->assertText(t('hook_modules_enabled fired for @module', array('@module' => $module_to_enable)));
           $this->assertModules(array($module_to_enable), TRUE);
           $this->assertModuleTablesExist($module_to_enable);
-          $this->assertModuleConfigFilesExist($module_to_enable);
+          $this->assertModuleConfig($module_to_enable);
           $this->assertLogMessage('system', "%module module installed.", array('%module' => $module_to_enable), WATCHDOG_INFO);
           $this->assertLogMessage('system', "%module module enabled.", array('%module' => $module_to_enable), WATCHDOG_INFO);
         }
@@ -374,7 +359,7 @@ class EnableDisableTestCase extends ModuleTestCase {
     //  Check that the module's database tables still exist.
     $this->assertModuleTablesExist($module);
     //  Check that the module's config files still exist.
-    $this->assertModuleConfigFilesExist($module);
+    $this->assertModuleConfig($module);
 
     // Uninstall the module.
     $edit = array();
@@ -396,7 +381,7 @@ class EnableDisableTestCase extends ModuleTestCase {
     // Check that the module's database tables no longer exist.
     $this->assertModuleTablesDoNotExist($module);
     // Check that the module's config files no longer exist.
-    $this->assertModuleConfigFilesDoNotExist($module);
+    $this->assertNoModuleConfig($module);
   }
 }