diff --git a/core/lib/Drupal/Core/DrupalKernel.php b/core/lib/Drupal/Core/DrupalKernel.php
index 92054d7..f167755 100644
--- a/core/lib/Drupal/Core/DrupalKernel.php
+++ b/core/lib/Drupal/Core/DrupalKernel.php
@@ -34,8 +34,19 @@ class DrupalKernel extends Kernel implements DrupalKernelInterface {
    * Holds the list of enabled modules.
    *
    * @var array
+   *   An associative array whose keys are module names and whose values are
+   *   ignored.
    */
-  protected $moduleList = array();
+  protected $moduleList;
+
+  /**
+   * Holds an updated list of enabled modules.
+   *
+   * @var array
+   *   An associative array whose keys are module names and whose values are
+   *   ignored.
+   */
+  protected $newModuleList;
 
   /**
    * An array of module data objects.
@@ -123,11 +134,10 @@ public function registerBundles() {
     $bundles = array(
       new CoreBundle(),
     );
-    if (!$this->moduleList) {
+    if (!isset($this->moduleList)) {
       $storage = new FileStorage(config_get_config_directory());
       $module_list = $storage->read('system.module');
-      $module_list = $module_list['enabled'];
-      $this->moduleList = $module_list;
+      $this->moduleList = isset($module_list['enabled']) ? $module_list['enabled'] : array();
     }
 
     $namespaces = $this->classLoader->getNamespaces();
@@ -186,7 +196,7 @@ protected function moduleData($module) {
    * Implements Drupal\Core\DrupalKernelInterface::updateModules().
    */
   public function updateModules(array $module_list, array $module_paths = array(), ContainerBuilder $base_container = NULL) {
-    $this->moduleList = $module_list;
+    $this->newModuleList = $module_list;
     foreach ($module_paths as $module => $path) {
       $this->moduleData[$module] = (object) array('uri' => $path);
     }
@@ -223,25 +233,27 @@ protected function getClassName() {
    */
   protected function initializeContainer() {
     $this->container = NULL;
-    $class = $this->getClassName();
-    $cache_file = $class . '.php';
 
-    // First, try to load.
-    if ($this->storage && !class_exists($class, FALSE)) {
-      $this->storage->load($cache_file);
-    }
-    // If the load succeeded or the class already existed, use it.
-    if (class_exists($class, FALSE)) {
-      $fully_qualified_class_name = '\\' . $class;
-      $this->container = new $fully_qualified_class_name;
-    }
+    if ($this->storage) {
+      $class = $this->getClassName();
+      $cache_file = $class . '.php';
 
-    if (isset($this->container)) {
-      $module_list = array_keys($this->moduleList ?: $this->container->get('config.factory')->get('system.module')->load()->get('enabled'));
-      if ($module_list !== $this->container->getParameter('container.modules')) {
-        unset($this->container);
+      // First, try to load.
+      if (!class_exists($class, FALSE)) {
+        $this->storage->load($cache_file);
+      }
+      // If the load succeeded or the class already existed, use it.
+      if (class_exists($class, FALSE)) {
+        $fully_qualified_class_name = '\\' . $class;
+        $this->container = new $fully_qualified_class_name;
       }
     }
+
+    if (isset($this->moduleList) && isset($this->newModuleList) && array_keys($this->moduleList) !== array_keys($this->newModuleList)) {
+      unset($this->container);
+      $this->moduleList = $this->newModuleList;
+      unset($this->newModuleList);
+    }
     if (!isset($this->container)) {
       $this->container = $this->buildContainer();
       if ($this->storage && !$this->dumpDrupalContainer($this->container, $this->getContainerBaseClass())) {
diff --git a/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php
index bfbca8f..84022d5 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php
@@ -98,7 +98,7 @@ protected function setUp() {
     $this->baseContainer = clone $this->container;
 
     // Bootstrap the kernel.
-    $this->kernel = new DrupalKernel('testing', TRUE, array_keys($this->moduleList));
+    $this->kernel = new DrupalKernel('testing', TRUE, drupal_classloader());
     $this->kernel->boot();
     $this->container = drupal_container();
 
@@ -204,8 +204,11 @@ protected function installSchema($module, $table) {
    */
   protected function enableModules(array $modules, $install = TRUE) {
     // Set the modules in the fixed module_list().
+    $module_config = config('system.module');
+    $new_enabled = array();
     foreach ($modules as $module) {
       $this->moduleList[$module]['filename'] = drupal_get_filename('module', $module);
+      $new_enabled[$module] = dirname($this->moduleList[$module]['filename']);
       module_list(NULL, $this->moduleList);
 
       // Call module_enable() to enable (install) the new module.
@@ -228,7 +231,7 @@ protected function enableModules(array $modules, $install = TRUE) {
       module_implements_reset();
     }
     $kernel = $this->container->get('kernel');
-    $kernel->updateModules(array_keys($this->moduleList), clone $this->baseContainer);
+    $kernel->updateModules($this->moduleList, $new_enabled, clone $this->baseContainer);
   }
 
 }