diff --git a/core/lib/Drupal/Core/CoreServiceProvider.php b/core/lib/Drupal/Core/CoreServiceProvider.php
index 8f4f66c..de7116a 100644
--- a/core/lib/Drupal/Core/CoreServiceProvider.php
+++ b/core/lib/Drupal/Core/CoreServiceProvider.php
@@ -53,6 +53,7 @@ public function register(ContainerBuilder $container) {
     $this->registerTwig($container);
     $this->registerModuleHandler($container);
     $this->registerUuid($container);
+    $this->registerTest($container);
 
     // Add the compiler pass that lets service providers modify existing
     // service definitions. This pass must come first so that later
@@ -170,4 +171,20 @@ public static function registerUuid(ContainerBuilder $container) {
     return $uuid_class;
   }
 
+  /**
+   * Registers services and event subscribers for a site under test.
+   */
+  protected function registerTest(ContainerBuilder $container) {
+    // Do nothing in case we are not in a test environment.
+    if (!drupal_valid_test_ua()) {
+      return;
+    }
+    // Add the HTTP request subscriber to Guzzle.
+    $container->register('http_client.test.subscriber', 'Drupal\Core\Test\EventSubscriber\TestHttpRequestSubscriber');
+    $definition = $container->getDefinition('http_default_client');
+    $definition->addMethodCall('addSubscriber', array(
+      new Reference('http_client.test.subscriber'),
+    ));
+  }
+
 }
diff --git a/core/lib/Drupal/Core/Http/Plugin/SimpletestHttpRequestSubscriber.php b/core/lib/Drupal/Core/Test/EventSubscriber/TestHttpRequestSubscriber.php
similarity index 76%
rename from core/lib/Drupal/Core/Http/Plugin/SimpletestHttpRequestSubscriber.php
rename to core/lib/Drupal/Core/Test/EventSubscriber/TestHttpRequestSubscriber.php
index 3db5def..3acaf0c 100644
--- a/core/lib/Drupal/Core/Http/Plugin/SimpletestHttpRequestSubscriber.php
+++ b/core/lib/Drupal/Core/Test/EventSubscriber/TestHttpRequestSubscriber.php
@@ -1,19 +1,19 @@
 <?php
+
 /**
  * @file
- * Contains Drupal\Core\Http\Plugin\SimpletestHttpRequestSubscriber
+ * Contains \Drupal\Core\Test\EventSubscriber\TestHttpRequestSubscriber.
  */
 
-namespace Drupal\Core\Http\Plugin;
+namespace Drupal\Core\Test\EventSubscriber;
 
 use Guzzle\Common\Event;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 
 /**
- * Subscribe to HTTP requests and override the User-Agent header if the request
- * is being dispatched from inside a simpletest.
+ * Overrides the User-Agent HTTP header for outbound HTTP requests.
  */
-class SimpletestHttpRequestSubscriber implements EventSubscriberInterface {
+class TestHttpRequestSubscriber implements EventSubscriberInterface {
 
   /**
    * {@inheritdoc}
@@ -36,4 +36,5 @@ public function onBeforeSendRequest(Event $event) {
       $event['request']->setHeader('User-Agent', drupal_generate_test_ua($test_prefix));
     }
   }
+
 }
diff --git a/core/profiles/testing/lib/Drupal/testing/TestingServiceProvider.php b/core/profiles/testing/lib/Drupal/testing/TestingServiceProvider.php
deleted file mode 100644
index 2b61fd0..0000000
--- a/core/profiles/testing/lib/Drupal/testing/TestingServiceProvider.php
+++ /dev/null
@@ -1,37 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\Core\Test\TestingServiceProvider.
- */
-
-namespace Drupal\testing;
-
-use Drupal\Core\DependencyInjection\ContainerBuilder;
-use Drupal\Core\DependencyInjection\ServiceModifierInterface;
-use Drupal\Core\DependencyInjection\ServiceProviderInterface;
-use Symfony\Component\DependencyInjection\Reference;
-
-/**
- * Service provider for testing profile.
- */
-class TestingServiceProvider implements ServiceProviderInterface, ServiceModifierInterface {
-
-  /**
-   * {@inheritdoc}
-   */
-  function register(ContainerBuilder $container) {
-    // Add the simpletest subscriber for guzzle.
-    $container->register('http_client_simpletest_subscriber', 'Drupal\Core\Http\Plugin\SimpletestHttpRequestSubscriber');
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function alter(ContainerBuilder $container) {
-    // Overrides language_manager class to test domain language negotiation.
-    $definition = $container->getDefinition('http_default_client');
-    $definition->addMethodCall('addSubscriber', array(new Reference('http_client_simpletest_subscriber')));
-  }
-
-}