interdiff impossible; taking evasive action
reverted:
--- b/core/lib/Drupal/Core/CoreBundle.php
+++ a/core/lib/Drupal/Core/CoreBundle.php
@@ -302,16 +302,6 @@
 
     $container->register('plugin.manager.condition', 'Drupal\Core\Condition\ConditionManager');
 
-    // Register image toolkit manager.
-    $container
-      ->register('image.toolkit.manager', 'Drupal\system\Plugin\ImageToolkitManager')
-      ->addArgument('%container.namespaces%');
-    // Register image toolkit.
-    $container
-      ->register('image.toolkit', 'Drupal\system\Plugin\ImageToolkitInterface')
-      ->setFactoryService('image.toolkit.manager')
-      ->setFactoryMethod('getDefaultToolkit');
-
     $container->register('kernel_destruct_subscriber', 'Drupal\Core\EventSubscriber\KernelDestructionSubscriber')
       ->addMethodCall('setContainer', array(new Reference('service_container')))
       ->addTag('event_subscriber');
unchanged:
--- a/core/lib/Drupal/Core/CoreBundle.php
+++ b/core/lib/Drupal/Core/CoreBundle.php
@@ -309,6 +309,16 @@ public function build(ContainerBuilder $container) {
     $container->register('ajax.subscriber', 'Drupal\Core\Ajax\AjaxSubscriber')
       ->addTag('event_subscriber');
 
+    // Register image toolkit manager.
+    $container
+      ->register('image.toolkit.manager', 'Drupal\system\Plugin\ImageToolkitManager')
+      ->addArgument('%container.namespaces%');
+    // Register image toolkit.
+    $container
+      ->register('image.toolkit', 'Drupal\system\Plugin\ImageToolkitInterface')
+      ->setFactoryService('image.toolkit.manager')
+      ->setFactoryMethod('getDefaultToolkit');
+
     $container->addCompilerPass(new RegisterMatchersPass());
     $container->addCompilerPass(new RegisterRouteFiltersPass());
     // Add a compiler pass for registering event subscribers.
diff -u b/core/modules/system/lib/Drupal/system/Tests/Image/ToolkitGdTest.php b/core/modules/system/lib/Drupal/system/Tests/Image/ToolkitGdTest.php
--- b/core/modules/system/lib/Drupal/system/Tests/Image/ToolkitGdTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Image/ToolkitGdTest.php
@@ -7,13 +7,13 @@
 
 namespace Drupal\system\Tests\Image;
 
-use Drupal\simpletest\WebTestBase;
+use Drupal\simpletest\DrupalUnitTestBase;
 use Drupal\system\Plugin\ImageToolkitManager;
 
 /**
  * Test the core GD image manipulation functions.
  */
-class ToolkitGdTest extends WebTestBase {
+class ToolkitGdTest extends DrupalUnitTestBase {
   // Colors that are used in testing.
   protected $black       = array(0, 0, 0, 0);
   protected $red         = array(255, 0, 0, 0);
@@ -27,6 +27,13 @@
   protected $width = 40;
   protected $height = 20;
 
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = array('system', 'simpletest');
+
   public static function getInfo() {
     return array(
       'name' => 'Image GD manipulation tests',
@@ -36,9 +43,14 @@
   }
 
   protected function checkRequirements() {
-    $manager = new ImageToolkitManager($this->container->getParameter('container.namespaces'));
-    $definition = $manager->getDefinition('gd');
-    if (!call_user_func($definition['class'] . '::isAvailable')) {
+    $gd_available = FALSE;
+    if ($check = get_extension_funcs('gd')) {
+      if (in_array('imagegd2', $check)) {
+        // GD2 support is available.
+        $gd_available =  TRUE;
+      }
+    }
+    if (!$gd_available) {
       return array(
         'Image manipulations for the GD toolkit cannot run because the GD toolkit is not available.',
       );
@@ -247,7 +259,7 @@
           $correct_dimensions_object = FALSE;
         }
 
-        $directory = file_default_scheme() . '://imagetests';
+        $directory = $this->public_files_directory .'/imagetest';
         file_prepare_directory($directory, FILE_CREATE_DIRECTORY);
         image_save($image, $directory . '/' . $op . '.' . $image->info['extension']);