diff --git a/core/includes/config.inc b/core/includes/config.inc
index 1e638ca..51476b7 100644
--- a/core/includes/config.inc
+++ b/core/includes/config.inc
@@ -154,7 +154,7 @@ function config_import_invoke_owner(array $config_changes, StorageInterface $sou
       // Check whether the module implements hook_config_import() and ask it to
       // handle the configuration change.
       $handled_by_module = FALSE;
-      if (module_hook($module, 'config_import')) {
+      if (module_hook($module, 'config_import_' . $op)) {
         $old_config = new Config($storage_dispatcher);
         $old_config
           ->setName($name)
@@ -167,7 +167,7 @@ function config_import_invoke_owner(array $config_changes, StorageInterface $sou
           $new_config->setData($data);
         }
 
-        $handled_by_module = module_invoke($module, 'config_import', $op, $name, $new_config, $old_config);
+        $handled_by_module = module_invoke($module, 'config_import_' . $op, $name, $new_config, $old_config);
       }
       if (!empty($handled_by_module)) {
         unset($config_changes[$op][$key]);
diff --git a/core/lib/Drupal/Core/Config/NullStorage.php b/core/lib/Drupal/Core/Config/NullStorage.php
index 54554c9..fede4f0 100644
--- a/core/lib/Drupal/Core/Config/NullStorage.php
+++ b/core/lib/Drupal/Core/Config/NullStorage.php
@@ -8,7 +8,18 @@
 namespace Drupal\Core\Config;
 
 /**
- * Defines the Null storage controller.
+ * Defines a stub storage controller.
+ *
+ * This storage is always empty; the controller reads and writes nothing.
+ *
+ * The stub implementation is needed for synchronizing configuration during
+ * installation of a module, in which case all configuration being shipped with
+ * the module is known to be new. Therefore, the module installation process is
+ * able to short-circuit the full diff against the active store; the diff would
+ * yield all currently available configuration as items to remove, since they do
+ * not exist in the module's default configuration directory.
+ *
+ * This also can be used for testing purposes.
  */
 class NullStorage implements StorageInterface {
   /**
diff --git a/core/modules/config/config.api.php b/core/modules/config/config.api.php
index 8cfa336..f0c3afa 100644
--- a/core/modules/config/config.api.php
+++ b/core/modules/config/config.api.php
@@ -13,19 +13,16 @@
  */
 
 /**
- * Synchronize configuration changes.
+ * Create configuration upon synchronizing configuration changes.
  *
  * This callback is invoked when configuration is synchronized between storages
  * and allows a module to take over the synchronization of configuration data.
  *
  * Modules should implement this callback if they manage configuration data
- * (such as image styles, node types, or fields), which needs to be
+ * (such as image styles, node types, or fields) which needs to be
  * prepared and passed through module API functions to properly handle a
  * configuration change.
  *
- * @param string $op
- *   The operation to perform for the configuration data; one of 'create',
- *   'delete', or 'change'.
  * @param string $name
  *   The name of the configuration object.
  * @param Drupal\Core\Config\Config $new_config
@@ -33,31 +30,78 @@
  * @param Drupal\Core\Config\Config $old_config
  *   A configuration object containing the old configuration data.
  */
-function MODULE_config_import($op, $name, $new_config, $old_config) {
+function MODULE_config_import_create($name, $new_config, $old_config) {
   // Only configurable thingies require custom handling. Any other module
   // settings can be synchronized directly.
   if (strpos($name, 'config_test.dynamic.') !== 0) {
     return FALSE;
   }
+  $config_test = new ConfigTest($new_config);
+  $config_test->save();
+  return TRUE;
+}
 
-  if ($op == 'delete') {
-    // @todo image_style_delete() supports the notion of a "replacement style"
-    //   to be used by other modules instead of the deleted style. Essential!
-    //   But that is impossible currently, since the config system only knows
-    //   about deleted and added changes. Introduce an 'old_ID' key within
-    //   config objects as a standard?
-    $config_test = new ConfigTest($old_config);
-    $config_test->delete();
-  }
-  if ($op == 'create') {
-    $config_test = new ConfigTest($new_config);
-    $config_test->save();
+/**
+ * Update configuration upon synchronizing configuration changes.
+ *
+ * This callback is invoked when configuration is synchronized between storages
+ * and allows a module to take over the synchronization of configuration data.
+ *
+ * Modules should implement this callback if they manage configuration data
+ * (such as image styles, node types, or fields) which needs to be
+ * prepared and passed through module API functions to properly handle a
+ * configuration change.
+ *
+ * @param string $name
+ *   The name of the configuration object.
+ * @param Drupal\Core\Config\Config $new_config
+ *   A configuration object containing the new configuration data.
+ * @param Drupal\Core\Config\Config $old_config
+ *   A configuration object containing the old configuration data.
+ */
+function MODULE_config_import_change($name, $new_config, $old_config) {
+  // Only configurable thingies require custom handling. Any other module
+  // settings can be synchronized directly.
+  if (strpos($name, 'config_test.dynamic.') !== 0) {
+    return FALSE;
   }
-  if ($op == 'change') {
-    $config_test = new ConfigTest($new_config);
-    $config_test->setOriginal($old_config);
-    $config_test->save();
+  $config_test = new ConfigTest($new_config);
+  $config_test->setOriginal($old_config);
+  $config_test->save();
+  return TRUE;
+}
+
+/**
+ * Delete configuration upon synchronizing configuration changes.
+ *
+ * This callback is invoked when configuration is synchronized between storages
+ * and allows a module to take over the synchronization of configuration data.
+ *
+ * Modules should implement this callback if they manage configuration data
+ * (such as image styles, node types, or fields) which needs to be
+ * prepared and passed through module API functions to properly handle a
+ * configuration change.
+ *
+ * @param string $name
+ *   The name of the configuration object.
+ * @param Drupal\Core\Config\Config $new_config
+ *   A configuration object containing the new configuration data.
+ * @param Drupal\Core\Config\Config $old_config
+ *   A configuration object containing the old configuration data.
+ */
+function MODULE_config_import_delete($name, $new_config, $old_config) {
+  // Only configurable thingies require custom handling. Any other module
+  // settings can be synchronized directly.
+  if (strpos($name, 'config_test.dynamic.') !== 0) {
+    return FALSE;
   }
+  // @todo image_style_delete() supports the notion of a "replacement style"
+  //   to be used by other modules instead of the deleted style. Essential!
+  //   But that is impossible currently, since the config system only knows
+  //   about deleted and added changes. Introduce an 'old_ID' key within
+  //   config objects as a standard?
+  $config_test = new ConfigTest($old_config);
+  $config_test->delete();
   return TRUE;
 }
 
diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigConfigurableTest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigConfigurableTest.php
deleted file mode 100644
index 68df5f1..0000000
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigConfigurableTest.php
+++ /dev/null
@@ -1,80 +0,0 @@
-<?php
-
-/**
- * @file
- * Definition of Drupal\config\Tests\ConfigConfigurableTest.
- */
-
-namespace Drupal\config\Tests;
-
-use Drupal\simpletest\WebTestBase;
-
-/**
- * Tests configurable configuration.
- */
-class ConfigConfigurableTest extends WebTestBase {
-  public static function getInfo() {
-    return array(
-      'name' => 'Configurable configuration',
-      'description' => 'Tests configurable configuration.',
-      'group' => 'Configuration',
-    );
-  }
-
-  function setUp() {
-    parent::setUp(array('config_test'));
-  }
-
-  /**
-   * Tests basic CRUD operations through the UI.
-   */
-  function testCRUD() {
-    // Create a thingie.
-    $id = 'thingie';
-    $edit = array(
-      'id' => $id,
-      'name' => 'Thingie',
-    );
-    $this->drupalPost('admin/structure/config_test/add', $edit, 'Save');
-    $this->assertResponse(200);
-    $this->assertText('Thingie');
-
-    // Update the thingie.
-    $this->assertLinkByHref('admin/structure/config_test/manage/' . $id);
-    $edit = array(
-      'name' => 'Thongie',
-    );
-    $this->drupalPost('admin/structure/config_test/manage/' . $id, $edit, 'Save');
-    $this->assertResponse(200);
-    $this->assertNoText('Thingie');
-    $this->assertText('Thongie');
-
-    // Delete the thingie.
-    $this->assertLinkByHref('admin/structure/config_test/manage/' . $id . '/delete');
-    $this->drupalPost('admin/structure/config_test/manage/' . $id . '/delete', array(), 'Delete');
-    $this->assertResponse(200);
-    $this->assertNoText('Thingie');
-    $this->assertNoText('Thongie');
-
-    // Re-create a thingie.
-    $edit = array(
-      'id' => $id,
-      'name' => 'Thingie',
-    );
-    $this->drupalPost('admin/structure/config_test/add', $edit, 'Save');
-    $this->assertResponse(200);
-    $this->assertText('Thingie');
-
-    // Rename the thingie's ID/machine name.
-    $this->assertLinkByHref('admin/structure/config_test/manage/' . $id);
-    $new_id = 'zingie';
-    $edit = array(
-      'id' => $new_id,
-      'name' => 'Zingie',
-    );
-    $this->drupalPost('admin/structure/config_test/manage/' . $id, $edit, 'Save');
-    $this->assertResponse(200);
-    $this->assertNoText('Thingie');
-    $this->assertText('Zingie');
-  }
-}
diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigInstallTest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigInstallTest.php
index 3d13d98..7ec6d8e 100644
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigInstallTest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigInstallTest.php
@@ -46,13 +46,5 @@ class ConfigInstallTest extends WebTestBase {
     // Verify that configuration import callback was invoked for the dynamic
     // thingie.
     $this->assertTrue($GLOBALS['hook_config_import']);
-
-    // Verify that config_test API hooks were invoked for the dynamic default
-    // thingie.
-    $this->assertTrue($GLOBALS['hook_config_test_load']);
-    $this->assertTrue($GLOBALS['hook_config_test_presave']);
-    $this->assertTrue($GLOBALS['hook_config_test_insert']);
-    $this->assertFalse(isset($GLOBALS['hook_config_test_update']));
-    $this->assertFalse(isset($GLOBALS['hook_config_test_delete']));
   }
 }
diff --git a/core/modules/config/tests/config_test/config/config_test.dynamic.default.yml b/core/modules/config/tests/config_test/config/config_test.dynamic.default.yml
index d285439..3e50e3b 100644
--- a/core/modules/config/tests/config_test/config/config_test.dynamic.default.yml
+++ b/core/modules/config/tests/config_test/config/config_test.dynamic.default.yml
@@ -1,2 +1,2 @@
 id: default
-name: Default
+label: Default
diff --git a/core/modules/config/tests/config_test/config_test.hooks.inc b/core/modules/config/tests/config_test/config_test.hooks.inc
deleted file mode 100644
index 56f690f..0000000
--- a/core/modules/config/tests/config_test/config_test.hooks.inc
+++ /dev/null
@@ -1,45 +0,0 @@
-<?php
-
-/**
- * @file
- * Fake third-party hook implementations for ConfigTest/config_test thingies.
- *
- * Testing the module/hook system is not the purpose of this test helper module.
- * Therefore, this file implements hooks on behalf of config_test module for
- * config_test thingie hooks themselves.
- */
-
-/**
- * Implements hook_config_test_load().
- */
-function config_test_config_test_load() {
-  $GLOBALS['hook_config_test_load'] = __FUNCTION__;
-}
-
-/**
- * Implements hook_config_test_presave().
- */
-function config_test_config_test_presave() {
-  $GLOBALS['hook_config_test_presave'] = __FUNCTION__;
-}
-
-/**
- * Implements hook_config_test_insert().
- */
-function config_test_config_test_insert() {
-  $GLOBALS['hook_config_test_insert'] = __FUNCTION__;
-}
-
-/**
- * Implements hook_config_test_update().
- */
-function config_test_config_test_update() {
-  $GLOBALS['hook_config_test_update'] = __FUNCTION__;
-}
-
-/**
- * Implements hook_config_test_delete().
- */
-function config_test_config_test_delete() {
-  $GLOBALS['hook_config_test_delete'] = __FUNCTION__;
-}
diff --git a/core/modules/config/tests/config_test/config_test.module b/core/modules/config/tests/config_test/config_test.module
index e4b14ab..6fd84a2 100644
--- a/core/modules/config/tests/config_test/config_test.module
+++ b/core/modules/config/tests/config_test/config_test.module
@@ -1,234 +1,50 @@
 <?php
 
-use Drupal\Core\Config\ConfigException;
-use Drupal\config_test\ConfigTest;
-
-require_once dirname(__FILE__) . '/config_test.hooks.inc';
-
 /**
- * Implements hook_config_import().
+ * Implements MODULE_config_import_create().
  */
-function config_test_config_import($op, $name, $new_config, $old_config) {
-  // Set a global value we can check in test code.
-  $GLOBALS['hook_config_import'] = __FUNCTION__;
-
+function config_test_config_import_create($name, $new_config, $old_config) {
   // Only configurable thingies require custom handling. Any other module
   // settings can be synchronized directly.
   if (strpos($name, 'config_test.dynamic.') !== 0) {
     return FALSE;
   }
+  // Set a global value we can check in test code.
+  $GLOBALS['hook_config_import'] = __FUNCTION__;
 
-  if ($op == 'delete') {
-    $config_test = new ConfigTest($old_config);
-    $config_test->delete();
-  }
-  if ($op == 'create') {
-    $config_test = new ConfigTest($new_config);
-    $config_test->save();
-  }
-  if ($op == 'change') {
-    $config_test = new ConfigTest($new_config);
-    $config_test->setOriginal($old_config);
-    $config_test->save();
-  }
+  $new_config->save();
   return TRUE;
 }
 
 /**
- * Implements hook_menu().
- */
-function config_test_menu() {
-  $items['admin/structure/config_test'] = array(
-    'title' => 'Test configuration',
-    'page callback' => 'config_test_list_page',
-    'access callback' => TRUE,
-  );
-  $items['admin/structure/config_test/add'] = array(
-    'title' => 'Add test configuration',
-    'page callback' => 'drupal_get_form',
-    'page arguments' => array('config_test_form'),
-    'access callback' => TRUE,
-    'type' => MENU_LOCAL_ACTION,
-  );
-  $items['admin/structure/config_test/manage/%config_test'] = array(
-    'title' => 'Edit test configuration',
-    'page callback' => 'drupal_get_form',
-    'page arguments' => array('config_test_form', 4),
-    'access callback' => TRUE,
-  );
-  $items['admin/structure/config_test/manage/%config_test/edit'] = array(
-    'title' => 'Edit',
-    'type' => MENU_DEFAULT_LOCAL_TASK,
-    'weight' => -10,
-  );
-  $items['admin/structure/config_test/manage/%config_test/delete'] = array(
-    'title' => 'Delete',
-    'page callback' => 'drupal_get_form',
-    'page arguments' => array('config_test_delete_form', 4),
-    'access callback' => TRUE,
-    'type' => MENU_LOCAL_TASK,
-  );
-  return $items;
-}
-
-/**
- * Loads a ConfigTest object.
- *
- * @param string $id
- *   The ID of the ConfigTest object to load.
+ * Implements MODULE_config_import_change().
  */
-function config_test_load($id) {
-  $config = config('config_test.dynamic.' . $id);
-  if ($config->isNew()) {
+function config_test_config_import_change($name, $new_config, $old_config) {
+  // Only configurable thingies require custom handling. Any other module
+  // settings can be synchronized directly.
+  if (strpos($name, 'config_test.dynamic.') !== 0) {
     return FALSE;
   }
-  return new ConfigTest($config);
-}
-
-/**
- * Saves a ConfigTest object.
- *
- * @param Drupal\config_test\ConfigTest $config_test
- *   The ConfigTest object to save.
- */
-function config_test_save(ConfigTest $config_test) {
-  return $config_test->save();
-}
-
-/**
- * Deletes a ConfigTest object.
- *
- * @param string $id
- *   The ID of the ConfigTest object to delete.
- */
-function config_test_delete($id) {
-  $config = config('config_test.dynamic.' . $id);
-  $config_test = new ConfigTest($config);
-  return $config_test->delete();
-}
-
-/**
- * Page callback; Lists available ConfigTest objects.
- */
-function config_test_list_page() {
-  $config_names = config_get_storage_names_with_prefix('config_test.dynamic.');
-  $rows = array();
-  foreach ($config_names as $config_name) {
-    $config_test = new ConfigTest(config($config_name));
-    $row = array();
-    $row['name']['data'] = array(
-      '#type' => 'link',
-      '#title' => $config_test->getLabel(),
-      '#href' => $config_test->getUri(),
-    );
-    $row['delete']['data'] = array(
-      '#type' => 'link',
-      '#title' => t('Delete'),
-      '#href' => $config_test->getUri() . '/delete',
-    );
-    $rows[] = $row;
-  }
-  $build = array(
-    '#theme' => 'table',
-    '#header' => array('Name', 'Operations'),
-    '#rows' => $rows,
-    '#empty' => format_string('No test configuration defined. <a href="@add-url">Add some</a>', array(
-      '@add-url' => url('admin/structure/config_test/add'),
-    )),
-  );
-  return $build;
-}
-
-/**
- * Form constructor to add or edit a ConfigTest object.
- *
- * @param Drupal\config_test\ConfigTest $config_test
- *   (optional) An existing ConfigTest object to edit. If omitted, the form
- *   creates a new ConfigTest.
- */
-function config_test_form($form, &$form_state, ConfigTest $config_test = NULL) {
-  if (!isset($config_test)) {
-    $config_test = new ConfigTest(config(NULL));
-  }
-  $form_state['config_test'] = $config_test;
-
-  $form['name'] = array(
-    '#type' => 'textfield',
-    '#title' => 'Label',
-    '#default_value' => $config_test->getLabel(),
-    '#required' => TRUE,
-  );
-  $form['id'] = array(
-    '#type' => 'machine_name',
-    '#default_value' => $config_test->getId(),
-    '#required' => TRUE,
-    '#machine_name' => array(
-      'exists' => 'config_test_load',
-    ),
-  );
-  $form['style'] = array(
-    '#type' => 'select',
-    '#title' => 'Image style',
-    '#options' => array(),
-    '#default_value' => $config_test->get('style'),
-    '#access' => FALSE,
-  );
-  if (module_exists('image')) {
-    $form['style']['#access'] = TRUE;
-    $form['style']['#options'] = image_style_options();
-  }
-
-  $form['actions'] = array('#type' => 'actions');
-  $form['actions']['submit'] = array('#type' => 'submit', '#value' => 'Save');
+  // Set a global value we can check in test code.
+  $GLOBALS['hook_config_import'] = __FUNCTION__;
 
-  return $form;
+  $new_config->save();
+  return TRUE;
 }
 
 /**
- * Form submission handler for config_test_form().
+ * Implements MODULE_config_import_delete().
  */
-function config_test_form_submit($form, &$form_state) {
-  form_state_values_clean($form_state);
-
-  $config_test = $form_state['config_test'];
-
-  foreach ($form_state['values'] as $key => $value) {
-    $config_test->set($key, $value);
-  }
-  $config_test->save();
-
-  if (!empty($config_test->original)) {
-    drupal_set_message(format_string('%label configuration has been updated.', array('%label' => $config_test->getLabel())));
-  }
-  else {
-    drupal_set_message(format_string('%label configuration has been created.', array('%label' => $config_test->getLabel())));
+function config_test_config_import_delete($name, $new_config, $old_config) {
+  // Only configurable thingies require custom handling. Any other module
+  // settings can be synchronized directly.
+  if (strpos($name, 'config_test.dynamic.') !== 0) {
+    return FALSE;
   }
+  // Set a global value we can check in test code.
+  $GLOBALS['hook_config_import'] = __FUNCTION__;
 
-  $form_state['redirect'] = 'admin/structure/config_test';
-}
-
-/**
- * Form constructor to delete a ConfigTest object.
- *
- * @param Drupal\config_test\ConfigTest $config_test
- *   The ConfigTest object to delete.
- */
-function config_test_delete_form($form, &$form_state, ConfigTest $config_test) {
-  $form_state['config_test'] = $config_test;
-
-  $form['id'] = array('#type' => 'value', '#value' => $config_test->getId());
-  return confirm_form($form,
-    format_string('Are you sure you want to delete %label', array('%label' => $config_test->getLabel())),
-    'admin/structure/config_test',
-    NULL,
-    'Delete'
-  );
+  $old_config->delete();
+  return TRUE;
 }
 
-/**
- * Form submission handler for config_test_delete_form().
- */
-function config_test_delete_form_submit($form, &$form_state) {
-  $form_state['config_test']->delete();
-  $form_state['redirect'] = 'admin/structure/config_test';
-}
diff --git a/core/modules/config/tests/config_test/lib/Drupal/config_test/ConfigTest.php b/core/modules/config/tests/config_test/lib/Drupal/config_test/ConfigTest.php
deleted file mode 100644
index 5d95d50..0000000
--- a/core/modules/config/tests/config_test/lib/Drupal/config_test/ConfigTest.php
+++ /dev/null
@@ -1,187 +0,0 @@
-<?php
-
-/**
- * @file
- * Definition of Drupal\config_test\ConfigTest.
- */
-
-namespace Drupal\config_test;
-
-/**
- * Defines the ConfigTest configuration thingie.
- *
- * @todo At minimum, introduce a consistent interface for configurable thingies.
- * @todo Consider to introduce a ConfigObjectBase for all configurable thingies.
- */
-class ConfigTest {
-  /**
-   * The configuration object.
-   *
-   * @var Drupal\Core\Config\ConfigObject
-   */
-  protected $config;
-
-  /**
-   * The key of the thingie's ID (machine name).
-   *
-   * @var string
-   */
-  public $idKey = 'id';
-
-  /**
-   * The key of the thingie's label.
-   *
-   * @var string
-   */
-  public $labelKey = 'name';
-
-  /**
-   * The thingie's original ID, if any.
-   *
-   * @var string|null
-   */
-  public $originalId;
-
-  /**
-   * The original configuration object, if any, upon update.
-   *
-   * @var Drupal\Core\Config\ConfigObject
-   */
-  public $original;
-
-  // -- Custom properties start --
-
-  /**
-   * The image style to use.
-   *
-   * @var string
-   */
-  public $style;
-
-  // -- Custom properties end --
-
-  /**
-   * Constructs a new ConfigTest thingie.
-   */
-  public function __construct($config) {
-    $this->load($config);
-  }
-
-  /**
-   * Implements Drupal\Core\Config\ConfigObjectInterface::getConfigPrefix().
-   */
-  public function getConfigPrefix() {
-    return 'config_test.dynamic';
-  }
-
-  /**
-   * Implements ConfigObjectInterface::getName().
-   */
-  public function getConfigName() {
-    return $this->getConfigPrefix() . '.' . $this->getId;
-  }
-
-  /**
-   * Implements ConfigObjectInterface::getId().
-   */
-  public function getId() {
-    return $this->config->get($this->idKey);
-  }
-
-  /**
-   * Implements ConfigObjectInterface::isNew().
-   */
-  public function isNew() {
-    return isset($this->originalId);
-  }
-
-  /**
-   * Implements ConfigObjectInterface::getLabel().
-   */
-  public function getLabel() {
-    return $this->config->get($this->labelKey);
-  }
-
-  /**
-   * Implements ConfigObjectInterface::getUri().
-   */
-  public function getUri() {
-    // @todo Check whether this makes sense.
-    return 'admin/structure/config_test/manage/' . $this->getId();
-  }
-
-  /**
-   * Implements ConfigObjectInterface::get().
-   */
-  public function get($property_name, $langcode = NULL) {
-    return $this->config->get($property_name);
-  }
-
-  /**
-   * Implements ConfigObjectInterface::set().
-   */
-  public function set($property_name, $value, $langcode = NULL) {
-    return $this->config->set($property_name, $value);
-  }
-
-  /**
-   * Implements ConfigObjectInterface::setOriginal().
-   */
-  public function setOriginal($config) {
-    $this->original = $config;
-    $this->originalId = $config->get($this->idKey);
-    return $this;
-  }
-
-  /**
-   * Implements ConfigObjectInterface::load().
-   */
-  public function load($config) {
-    $this->config = $config;
-    $this->originalId = $config->get($this->idKey);
-    module_invoke_all('config_test_load', $this);
-    return $this;
-  }
-
-  /**
-   * Implements ConfigObjectInterface::save().
-   */
-  public function save() {
-    // Provide the original configuration in $config->original, if any.
-    if (isset($this->originalId)) {
-      $original_config = config($this->getConfigPrefix() . '.' . $this->originalId);
-      $this->setOriginal(new $this($original_config));
-    }
-
-    // Save the new configuration.
-    $this->config->setName($this->getConfigPrefix() . '.' . $this->getId());
-    module_invoke_all('config_test_presave', $this);
-    $this->config->save();
-
-    if (isset($this->originalId)) {
-      module_invoke_all('config_test_update', $this);
-      // Delete the original configuration, if it was renamed.
-      if ($this->originalId !== $this->getId()) {
-        // Configuration data is emptied out upon delete, so back it up and
-        // re-inject it. Delete the old configuration data directly; hooks will
-        // get and will be able to react to the data in $this->original.
-        $original_data = $original_config->get();
-        $original_config->delete();
-        $original_config->setData($original_data);
-      }
-    }
-    else {
-      module_invoke_all('config_test_insert', $this);
-    }
-
-    return $this;
-  }
-
-  /**
-   * Implements ConfigObjectInterface::delete().
-   */
-  public function delete() {
-    $this->config->delete();
-    module_invoke_all('config_test_delete', $this);
-  }
-}
diff --git a/core/modules/image/image.module b/core/modules/image/image.module
index 28afd0b..70f5ae5 100644
--- a/core/modules/image/image.module
+++ b/core/modules/image/image.module
@@ -500,32 +500,47 @@ function image_path_flush($path) {
 }
 
 /**
- * Implements hook_config_import().
+ * Implements MODULE_config_import_create().
  */
-function image_config_import($op, $name, $new_config, $old_config) {
+function image_config_import_create($name, $new_config, $old_config) {
   // Only image styles require custom handling. Any other module settings can be
   // synchronized directly.
   if (strpos($name, 'image.style.') !== 0) {
     return FALSE;
   }
+  $style = $new_config->get();
+  return image_style_save($style);
+}
 
-  if ($op == 'delete') {
-    // @todo image_style_delete() supports the notion of a "replacement style"
-    //   to be used by other modules instead of the deleted style. Essential!
-    //   But that is impossible currently, since the config system only knows
-    //   about deleted and added changes. Introduce an 'old_ID' key within
-    //   config objects as a standard?
-    $style = $old_config->get();
-    return image_style_delete($style);
-  }
-  if ($op == 'create') {
-    $style = $new_config->get();
-    return image_style_save($style);
+/**
+ * Implements MODULE_config_import_change().
+ */
+function image_config_import_change($name, $new_config, $old_config) {
+  // Only image styles require custom handling. Any other module settings can be
+  // synchronized directly.
+  if (strpos($name, 'image.style.') !== 0) {
+    return FALSE;
   }
-  if ($op == 'change') {
-    $style = $new_config->get();
-    return image_style_save($style);
+  $style = $new_config->get();
+  return image_style_save($style);
+}
+
+/**
+ * Implements MODULE_config_import_delete().
+ */
+function image_config_import_delete($name, $new_config, $old_config) {
+  // Only image styles require custom handling. Any other module settings can be
+  // synchronized directly.
+  if (strpos($name, 'image.style.') !== 0) {
+    return FALSE;
   }
+  // @todo image_style_delete() supports the notion of a "replacement style"
+  //   to be used by other modules instead of the deleted style. Essential!
+  //   But that is impossible currently, since the config system only knows
+  //   about deleted and added changes. Introduce an 'old_ID' key within
+  //   config objects as a standard?
+  $style = $old_config->get();
+  return image_style_delete($style);
 }
 
 /**