diff --git a/core/includes/module.inc b/core/includes/module.inc
index 542840e..02f5da3 100644
--- a/core/includes/module.inc
+++ b/core/includes/module.inc
@@ -518,8 +518,6 @@ function module_enable($module_list, $enable_dependencies = TRUE) {
 
       // Clear the entity info cache before importing new configuration.
       entity_info_cache_clear();
-      // Register the PSR-0 namespace of the enabled module.
-      drupal_classloader_register($module, dirname(drupal_get_filename('module', $module)));
 
       // Now install the module if necessary.
       if (drupal_get_installed_schema_version($module, TRUE) == SCHEMA_UNINSTALLED) {
diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigImportTest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigImportTest.php
index a4b2131..189d13b 100644
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigImportTest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigImportTest.php
@@ -14,6 +14,13 @@
  */
 class ConfigImportTest extends DrupalUnitTestBase {
 
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = array('config_test');
+
   public static function getInfo() {
     return array(
       'name' => 'Import configuration',
@@ -25,8 +32,6 @@ public static function getInfo() {
   function setUp() {
     parent::setUp();
 
-    $this->enableModules(array('config_test'));
-
     config_install_default_config('module', 'config_test');
     // Installing config_test's default configuration pollutes the global
     // variable being used for recording hook invocations by this test already,
diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigOverrideTest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigOverrideTest.php
index 3447ff0..de7784f 100644
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigOverrideTest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigOverrideTest.php
@@ -14,6 +14,13 @@
  */
 class ConfigOverrideTest extends DrupalUnitTestBase {
 
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = array('config_test');
+
   public static function getInfo() {
     return array(
       'name' => 'Configuration overrides',
@@ -25,8 +32,6 @@ public static function getInfo() {
   function setUp() {
     parent::setUp();
 
-    $this->enableModules(array('config_test'));
-
     config_install_default_config('module', 'config_test');
   }
 
diff --git a/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php b/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php
index a21d496..13b6c79 100644
--- a/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php
+++ b/core/modules/simpletest/lib/Drupal/simpletest/DrupalUnitTestBase.php
@@ -145,6 +145,8 @@ protected function enableModules(array $modules, $install = TRUE) {
     // Set the modules in the fixed module_list().
     foreach ($modules as $module) {
       $this->moduleList[$module]['filename'] = drupal_get_filename('module', $module);
+      // Register the PSR-0 namespace of the enabled module.
+      drupal_classloader_register($module, dirname($this->moduleList[$module]['filename'] ));
     }
     module_list(NULL, $this->moduleList);
 
diff --git a/core/modules/views/lib/Drupal/views/Tests/Plugin/JoinTest.php b/core/modules/views/lib/Drupal/views/Tests/Plugin/JoinTest.php
index d55e9e7..944db1f 100644
--- a/core/modules/views/lib/Drupal/views/Tests/Plugin/JoinTest.php
+++ b/core/modules/views/lib/Drupal/views/Tests/Plugin/JoinTest.php
@@ -38,7 +38,6 @@ protected function setUp() {
     drupal_classloader_register('views', dirname(drupal_get_filename('module', 'views')));
     drupal_classloader_register('views_test_data', dirname(drupal_get_filename('module', 'views_test_data')));
 
-
     // Add a join plugin manager which can be used in all of the tests.
     $this->manager = drupal_container()->get('plugin.manager.views.join');
   }