diff -u b/core/includes/config.inc b/core/includes/config.inc
--- b/core/includes/config.inc
+++ b/core/includes/config.inc
@@ -3,7 +3,6 @@
 use Drupal\Core\Config\Config;
 use Drupal\Core\Config\ConfigException;
 use Drupal\Core\Config\FileStorage;
-use Drupal\Core\Config\Context\ContextInterface;
 use Drupal\Core\Config\StorageInterface;
 
 /**
@@ -27,8 +26,7 @@
 function config_install_default_config($type, $name) {
   // Use the override free context for config importing so that any overrides do
   // not change the data on import.
-  $config_factory = drupal_container()->get('config.factory');
-  $config_factory->enterContext(drupal_container()->get('config.context.free'));
+  config_context_enter('config.context.free');
 
   // If this module defines any ConfigEntity types then create an empty
   // manifest file for each of them.
@@ -55,7 +53,7 @@
   }
   // Exit the override free context and ensure that any new manifest data is
   // available.
-  $config_factory
+  drupal_container()->get('config.factory')
     ->leaveContext()
     ->reset('manifest');
 }
@@ -129,7 +127,7 @@
   if (drupal_container()->has($context_name)) {
     $context = drupal_container()->get($context_name);
   }
-  elseif (class_exists($context_name)) {
+  elseif (class_exists($context_name) && in_array("Drupal\\Core\\Config\\Context\\ContextInterface", class_implements($context_name))) {
     $context = drupal_container()
       ->get('config.context.factory')
       ->get($context_name);
@@ -265,15 +263,14 @@
   try {
     // Use the override free context for config importing so that any overrides do
     // not change the data on import.
-    $config_factory = drupal_container()->get('config.factory');
-    $config_factory->enterContext(drupal_container()->get('config.context.free'));
+    config_context_enter('config.context.free');
 
     $remaining_changes = config_import_invoke_owner($config_changes, $source_storage, $target_storage);
     config_sync_changes($remaining_changes, $source_storage, $target_storage);
 
     // Exit the override free context and ensure that any new manifest data is
     // available.
-    $config_factory
+    drupal_container()->get('config.factory')
       ->leaveContext()
       ->reset('manifest');
   }
diff -u b/core/modules/config/lib/Drupal/config/Tests/ConfigLocaleOverride.php b/core/modules/config/lib/Drupal/config/Tests/ConfigLocaleOverride.php
--- b/core/modules/config/lib/Drupal/config/Tests/ConfigLocaleOverride.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigLocaleOverride.php
@@ -85,7 +85,7 @@
     ));
     $config_factory = drupal_container()->get('config.factory');
 
-    $user_config_context = config_context_enter('Drupal\user\UserConfigContext');
+    $user_config_context = config_context_enter("Drupal\\user\\UserConfigContext");
     $user_config_context->setAccount($account);
     $config = config('config_test.system');
     $this->assertIdentical($config->get('foo'), 'fr bar');
@@ -118,7 +118,7 @@
       'preferred_langcode' => 'en',
     ));
     // Create a new user config context to stack on top of the existign one.
-    $en_user_config_context = config_context_enter('Drupal\user\UserConfigContext');
+    $en_user_config_context = config_context_enter("Drupal\\user\\UserConfigContext");
     $en_user_config_context->setAccount($account);
     $config = config('config_test.system');
     $this->assertIdentical($config->get('foo'), 'en bar');
only in patch2:
unchanged:
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigCRUDTest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigCRUDTest.php
@@ -171,21 +171,13 @@ function testNameValidation() {
 
     // Write configuration with an invalid name (missing a namespace) to
     // staging.
-    $storage = $this->container->get('config.storage');
     $staging = $this->container->get('config.storage.staging');
     $manifest_data = config('manifest.invalid_object_name')->get();
     $manifest_data['new']['name'] = 'invalid';
     $staging->write('manifest.invalid_object_name', $manifest_data);
 
-    // Verify that an exception is thrown when synchronizing.
-    $message = 'Expected ConfigNameException was thrown when attempting to sync invalid configuration.';
-    try {
-      config_import();
-      $this->fail($message);
-    }
-    catch (ConfigNameException $e) {
-      $this->pass($message);
-    }
+    // Assert that config_import returns false indicating a failure.
+    $this->assertFalse(config_import(), "Config import failed when trying to importing an object with an invalid name");
   }
 
 }