diff --git a/core/modules/system/lib/Drupal/system/Tests/Module/DependencyTest.php b/core/modules/system/lib/Drupal/system/Tests/Module/DependencyTest.php
index 8fa84fe..d176fc3 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Module/DependencyTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Module/DependencyTest.php
@@ -11,6 +11,14 @@
  * Tests module dependency functionality.
  */
 class DependencyTest extends ModuleTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = array('system_test');
+
   public static function getInfo() {
     return array(
       'name' => 'Module dependencies',
diff --git a/core/modules/system/lib/Drupal/system/Tests/Module/EnableDisableTest.php b/core/modules/system/lib/Drupal/system/Tests/Module/EnableDisableTest.php
index e73ace9..1f86140 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Module/EnableDisableTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Module/EnableDisableTest.php
@@ -27,7 +27,8 @@ function testEnableDisable() {
     // hidden or required.
     $modules = system_rebuild_module_data();
     foreach ($modules as $name => $module) {
-      if ($module->info['package'] != 'Core' || !empty($module->info['hidden']) || !empty($module->info['required'])) {
+      // Skip all non-core modules, and all hidden or required modules.
+      if (strpos($module->uri, 'core/modules') !== 0 || !empty($module->info['hidden']) || !empty($module->info['required'])) {
         unset($modules[$name]);
       }
     }
@@ -88,7 +89,8 @@ function testEnableDisable() {
 
         // Install and enable the module.
         $edit = array();
-        $edit['modules[Core][' . $name . '][enable]'] = $name;
+        $package = $module->info['package'];
+        $edit['modules[' . $package . '][' . $name . '][enable]'] = $name;
         $this->drupalPost('admin/modules', $edit, t('Save configuration'));
         // Handle the case where modules were installed along with this one and
         // where we therefore hit a confirmation screen.
@@ -117,7 +119,7 @@ function testEnableDisable() {
         // for the dblog module, because that is needed for the test; we'll go
         // back and do that one at the end also.
         if ($name != 'dblog') {
-          $this->assertSuccessfulDisableAndUninstall($name);
+          $this->assertSuccessfulDisableAndUninstall($name, $package);
         }
       }
     }
@@ -127,13 +129,14 @@ function testEnableDisable() {
     while (!empty($automatically_enabled)) {
       $initial_count = count($automatically_enabled);
       foreach (array_keys($automatically_enabled) as $name) {
+        $package = $modules[$name]->info['package'];
         // If the module can't be disabled due to dependencies, skip it and try
         // again the next time. Otherwise, try to disable it.
         $this->drupalGet('admin/modules');
-        $disabled_checkbox = $this->xpath('//input[@type="checkbox" and @disabled="disabled" and @name="modules[Core][' . $name . '][enable]"]');
+        $disabled_checkbox = $this->xpath('//input[@type="checkbox" and @disabled="disabled" and @name="modules[' . $package . '][' . $name . '][enable]"]');
         if (empty($disabled_checkbox) && $name != 'dblog') {
           unset($automatically_enabled[$name]);
-          $this->assertSuccessfulDisableAndUninstall($name);
+          $this->assertSuccessfulDisableAndUninstall($name, $package);
         }
       }
       $final_count = count($automatically_enabled);
@@ -158,8 +161,8 @@ function testEnableDisable() {
     // - That enabling more than one module at the same time does not lead to
     //   any errors.
     $edit = array();
-    foreach (array_keys($modules) as $name) {
-      $edit['modules[Core][' . $name . '][enable]'] = $name;
+    foreach ($modules as $name => $module) {
+      $edit['modules[' . $module->info['package'] . '][' . $name . '][enable]'] = $name;
     }
     $this->drupalPost('admin/modules', $edit, t('Save configuration'));
     $this->assertText(t('The configuration options have been saved.'), 'Modules status has been updated.');
@@ -170,11 +173,13 @@ function testEnableDisable() {
    *
    * @param string $module
    *   The name of the module to disable and uninstall.
+   * @param string $package
+   *   The package of the module to disable and uninstall.
    */
-  function assertSuccessfulDisableAndUninstall($module) {
+  function assertSuccessfulDisableAndUninstall($module, $package = 'Core') {
     // Disable the module.
     $edit = array();
-    $edit['modules[Core][' . $module . '][enable]'] = FALSE;
+    $edit['modules[' . $package . '][' . $module . '][enable]'] = FALSE;
     $this->drupalPost('admin/modules', $edit, t('Save configuration'));
     $this->assertText(t('The configuration options have been saved.'), 'Modules status has been updated.');
     $this->assertModules(array($module), FALSE);
diff --git a/core/modules/system/lib/Drupal/system/Tests/Module/HookRequirementsTest.php b/core/modules/system/lib/Drupal/system/Tests/Module/HookRequirementsTest.php
index 1572f5d..cd008a2 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Module/HookRequirementsTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Module/HookRequirementsTest.php
@@ -11,6 +11,14 @@
  * Tests failure of hook_requirements('install').
  */
 class HookRequirementsTest extends ModuleTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = array('system_test');
+
   public static function getInfo() {
     return array(
       'name' => 'Requirements hook failure',
diff --git a/core/modules/system/lib/Drupal/system/Tests/Module/ModuleTestBase.php b/core/modules/system/lib/Drupal/system/Tests/Module/ModuleTestBase.php
index b7fd25c..6da6424 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Module/ModuleTestBase.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Module/ModuleTestBase.php
@@ -16,13 +16,6 @@
  */
 abstract class ModuleTestBase extends WebTestBase {
 
-  /**
-   * Modules to enable.
-   *
-   * @var array
-   */
-  public static $modules = array('system_test');
-
   protected $admin_user;
 
   function setUp() {
diff --git a/core/modules/system/lib/Drupal/system/Tests/Module/VersionTest.php b/core/modules/system/lib/Drupal/system/Tests/Module/VersionTest.php
index 467a395..965a4f1 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Module/VersionTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Module/VersionTest.php
@@ -17,7 +17,7 @@ class VersionTest extends ModuleTestBase {
    *
    * @var array
    */
-  public static $modules = array('module_test');
+  public static $modules = array('system_test', 'module_test');
 
   public static function getInfo() {
     return array(