diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigInstallWebTest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigInstallWebTest.php
index 7116bea..56d9a01 100644
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigInstallWebTest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigInstallWebTest.php
@@ -136,14 +136,14 @@ function testInstallProfileConfigOverwrite() {
     // Turn on the test module, which will attempt to replace the
     // configuration data. This attempt to replace the active configuration
     // should be ignored.
-    \Drupal::moduleHandler()->install(array('config_override_test'));
+    \Drupal::moduleHandler()->install(array('config_existing_default_config_test'));
 
     // Verify that the test module has not been able to change the data.
     $config = \Drupal::config($config_name);
     $this->assertIdentical($config->get(), $expected_profile_data);
 
     // Disable and uninstall the test module.
-    \Drupal::moduleHandler()->uninstall(array('config_override_test'));
+    \Drupal::moduleHandler()->uninstall(array('config_existing_default_config_test'));
 
     // Verify that the data hasn't been altered by removing the test module.
     $config = \Drupal::config($config_name);
diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigModuleOverridesTest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigModuleOverridesTest.php
index c5c7190..1c358c5 100644
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigModuleOverridesTest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigModuleOverridesTest.php
@@ -14,7 +14,7 @@
  */
 class ConfigModuleOverridesTest extends DrupalUnitTestBase {
 
-  public static $modules = array('system', 'config', 'config_override');
+  public static $modules = array('system', 'config', 'config_override_test');
 
   public static function getInfo() {
     return array(
@@ -55,11 +55,11 @@ public function testSimpleModuleOverrides() {
     // Test overrides of completely new configuration objects. In normal runtime
     // this should only happen for configuration entities as we should not be
     // creating simple configuration objects on the fly.
-    $config = $config_factory->get('config_override.new');
-    $this->assertTrue($config->isNew(), 'The configuration object config_override.new is new');
+    $config = $config_factory->get('config_override_test.new');
+    $this->assertTrue($config->isNew(), 'The configuration object config_override_test.new is new');
     $this->assertIdentical($config->get('module'), 'override');
     $config_factory->setOverrideState(FALSE);
-    $config = \Drupal::config('config_override.new');
+    $config = \Drupal::config('config_override_test.new');
     $this->assertIdentical($config->get('module'), NULL);
 
     $config_factory->setOverrideState($old_state);
diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigOtherModuleTest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigOtherModuleTest.php
index 9ba92da..c819cb6 100644
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigOtherModuleTest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigOtherModuleTest.php
@@ -39,29 +39,29 @@ public function setUp() {
    * Tests enabling the provider of the default configuration first.
    */
   public function testInstallOtherModuleFirst() {
-    $this->moduleHandler->install(array('config_other_module_config'));
+    $this->moduleHandler->install(array('config_other_module_config_test'));
 
     // Check that the config entity doesn't exist before the config_test module
     // is enabled. We cannot use the entity system because the config_test
     // entity type does not exist.
-    $config = $this->container->get('config.factory')->get('config_test.dynamic.other_module');
+    $config = $this->container->get('config.factory')->get('config_test.dynamic.other_module_test');
     $this->assertTrue($config->isNew(), 'Default configuration for other modules is not installed if that module is not enabled.');
 
     // Install the module that provides the entity type. This installs the
     // default configuration.
     $this->moduleHandler->install(array('config_test'));
-    $this->assertTrue(entity_load('config_test', 'other_module', TRUE), 'Default configuration has been installed.');
+    $this->assertTrue(entity_load('config_test', 'other_module_test', TRUE), 'Default configuration has been installed.');
 
     // Uninstall the module that provides the entity type. This will remove the
     // default configuration.
     $this->moduleHandler->uninstall(array('config_test'));
-    $config = $this->container->get('config.factory')->get('config_test.dynamic.other_module');
+    $config = $this->container->get('config.factory')->get('config_test.dynamic.other_module_test');
     $this->assertTrue($config->isNew(), 'Default configuration for other modules is removed when the config entity provider is disabled.');
 
     // Install the module that provides the entity type again. This installs the
     // default configuration.
     $this->moduleHandler->install(array('config_test'));
-    $other_module_config_entity = entity_load('config_test', 'other_module', TRUE);
+    $other_module_config_entity = entity_load('config_test', 'other_module_test', TRUE);
     $this->assertTrue($other_module_config_entity, "Default configuration has been recreated.");
 
     // Update the default configuration to test that the changes are preserved
@@ -70,15 +70,15 @@ public function testInstallOtherModuleFirst() {
     $other_module_config_entity->save();
 
     // Uninstall the module that provides the default configuration.
-    $this->moduleHandler->uninstall(array('config_other_module_config'));
-    $this->assertTrue(entity_load('config_test', 'other_module', TRUE), 'Default configuration for other modules is not removed when the module that provides it is uninstalled.');
+    $this->moduleHandler->uninstall(array('config_other_module_config_test'));
+    $this->assertTrue(entity_load('config_test', 'other_module_test', TRUE), 'Default configuration for other modules is not removed when the module that provides it is uninstalled.');
 
     // Default configuration provided by config_test should still exist.
     $this->assertTrue(entity_load('config_test', 'dotted.default', TRUE), 'The configuration is not deleted.');
 
     // Re-enable module to test that default config is unchanged.
-    $this->moduleHandler->install(array('config_other_module_config'));
-    $config_entity = entity_load('config_test', 'other_module', TRUE);
+    $this->moduleHandler->install(array('config_other_module_config_test'));
+    $config_entity = entity_load('config_test', 'other_module_test', TRUE);
     $this->assertEqual($config_entity->get('style'), "The piano ain't got no wrong notes.", 'Re-enabling the module does not install default config over the existing config entity.');
   }
 
@@ -87,10 +87,10 @@ public function testInstallOtherModuleFirst() {
    */
   public function testInstallConfigEnityModuleFirst() {
     $this->moduleHandler->install(array('config_test'));
-    $this->assertFalse(entity_load('config_test', 'other_module', TRUE), 'Default configuration provided by config_other_module_config does not exist.');
+    $this->assertFalse(entity_load('config_test', 'other_module_test', TRUE), 'Default configuration provided by config_other_module_config_test does not exist.');
 
-    $this->moduleHandler->install(array('config_other_module_config'));
-    $this->assertTrue(entity_load('config_test', 'other_module', TRUE), 'Default configuration provided by config_other_module_config has been installed.');
+    $this->moduleHandler->install(array('config_other_module_config_test'));
+    $this->assertTrue(entity_load('config_test', 'other_module_test', TRUE), 'Default configuration provided by config_other_module_config_test has been installed.');
   }
 
   /**
diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigOverridesPriorityTest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigOverridesPriorityTest.php
index 6deab96..44a4180 100644
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigOverridesPriorityTest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigOverridesPriorityTest.php
@@ -15,7 +15,7 @@
  */
 class ConfigOverridesPriorityTest extends DrupalUnitTestBase {
 
-  public static $modules = array('system', 'config', 'config_override', 'language');
+  public static $modules = array('system', 'config', 'config_override_test', 'language');
 
   public static function getInfo() {
     return array(
diff --git a/core/modules/config/tests/config_existing_default_config_test/config/system.cron.yml b/core/modules/config/tests/config_existing_default_config_test/config/system.cron.yml
new file mode 100644
index 0000000..79f797f
--- /dev/null
+++ b/core/modules/config/tests/config_existing_default_config_test/config/system.cron.yml
@@ -0,0 +1,5 @@
+threshold:
+  autorun: 0
+  requirements_warning: 172800
+  requirements_error: 1209600
+
diff --git a/core/modules/config/tests/config_existing_default_config_test/config_existing_default_config_test.yml b/core/modules/config/tests/config_existing_default_config_test/config_existing_default_config_test.yml
new file mode 100644
index 0000000..4163a85
--- /dev/null
+++ b/core/modules/config/tests/config_existing_default_config_test/config_existing_default_config_test.yml
@@ -0,0 +1,6 @@
+name: 'Configuration existing default config test'
+type: module
+package: Testing
+version: VERSION
+core: 8.x
+hidden: true
diff --git a/core/modules/config/tests/config_other_module_config_test/config/config_test.dynamic.other_module_test.yml b/core/modules/config/tests/config_other_module_config_test/config/config_test.dynamic.other_module_test.yml
new file mode 100644
index 0000000..a43f3a0
--- /dev/null
+++ b/core/modules/config/tests/config_other_module_config_test/config/config_test.dynamic.other_module_test.yml
@@ -0,0 +1,7 @@
+id: other_module_test
+label: 'Other module test'
+weight: 0
+style: ''
+status: true
+langcode: en
+protected_property: Default
diff --git a/core/modules/config/tests/config_other_module_config_test/config_other_module_config_test.info.yml b/core/modules/config/tests/config_other_module_config_test/config_other_module_config_test.info.yml
new file mode 100644
index 0000000..0f78017
--- /dev/null
+++ b/core/modules/config/tests/config_other_module_config_test/config_other_module_config_test.info.yml
@@ -0,0 +1,6 @@
+name: 'Config other module config'
+type: module
+package: Testing
+version: VERSION
+core: 8.x
+hidden: true
diff --git a/core/modules/config/tests/config_override/config_override.services.yml b/core/modules/config/tests/config_override/config_override.services.yml
deleted file mode 100644
index 5272a84..0000000
--- a/core/modules/config/tests/config_override/config_override.services.yml
+++ /dev/null
@@ -1,9 +0,0 @@
-services:
-  config_override.overrider:
-    class: Drupal\config_override\ConfigOverrider
-    tags:
-      - { name: config.factory.override}
-  config_override.low_priority_overrider:
-    class: Drupal\config_override\ConfigOverriderLowPriority
-    tags:
-      - { name: config.factory.override, priority: -100 }
diff --git a/core/modules/config/tests/config_override_test/config_override_test.info.yml b/core/modules/config/tests/config_override_test/config_override_test.info.yml
new file mode 100644
index 0000000..1ccb50b
--- /dev/null
+++ b/core/modules/config/tests/config_override_test/config_override_test.info.yml
@@ -0,0 +1,6 @@
+name: 'Configuration override test'
+type: module
+package: Testing
+version: VERSION
+core: 8.x
+hidden: true
diff --git a/core/modules/config/tests/config_override_test/config_override_test.module b/core/modules/config/tests/config_override_test/config_override_test.module
deleted file mode 100644
index f364ffb..0000000
--- a/core/modules/config/tests/config_override_test/config_override_test.module
+++ /dev/null
@@ -1,6 +0,0 @@
-<?php
-
-/**
- * @file
- * Test module containing a configuration file which matches another module.
- */
diff --git a/core/modules/config/tests/config_override_test/config_override_test.services.yml b/core/modules/config/tests/config_override_test/config_override_test.services.yml
new file mode 100644
index 0000000..c3fae64
--- /dev/null
+++ b/core/modules/config/tests/config_override_test/config_override_test.services.yml
@@ -0,0 +1,9 @@
+services:
+  config_override_test.overrider:
+    class: Drupal\config_override_test\ConfigOverrider
+    tags:
+      - { name: config.factory.override}
+  config_override_test.low_priority_overrider:
+    class: Drupal\config_override_test\ConfigOverriderLowPriority
+    tags:
+      - { name: config.factory.override, priority: -100 }
diff --git a/core/modules/config/tests/config_override_test/lib/Drupal/config_override_test/ConfigOverrider.php b/core/modules/config/tests/config_override_test/lib/Drupal/config_override_test/ConfigOverrider.php
new file mode 100644
index 0000000..266866a
--- /dev/null
+++ b/core/modules/config/tests/config_override_test/lib/Drupal/config_override_test/ConfigOverrider.php
@@ -0,0 +1,41 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\config_override_test\ConfigOverrider.
+ */
+
+namespace Drupal\config_override_test;
+
+use Drupal\Core\Config\ConfigFactoryOverrideInterface;
+
+/**
+ * Tests module overrides for configuration.
+ */
+class ConfigOverrider implements ConfigFactoryOverrideInterface {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function loadOverrides($names) {
+    $overrides = array();
+    if (!empty($GLOBALS['config_test_run_module_overrides'])) {
+      if (in_array('system.site', $names)) {
+        $overrides = $overrides + array('system.site' => array('name' => 'ZOMG overridden site name'));
+      }
+      if (in_array('config_override_test.new', $names)) {
+        $overrides = $overrides + array('config_override_test.new' => array('module' => 'override'));
+      }
+    }
+    return $overrides;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getCacheSuffix() {
+    return 'ConfigOverrider';
+  }
+
+}
+
diff --git a/core/modules/config/tests/config_override_test/lib/Drupal/config_override_test/ConfigOverriderLowPriority.php b/core/modules/config/tests/config_override_test/lib/Drupal/config_override_test/ConfigOverriderLowPriority.php
new file mode 100644
index 0000000..b1dd32d
--- /dev/null
+++ b/core/modules/config/tests/config_override_test/lib/Drupal/config_override_test/ConfigOverriderLowPriority.php
@@ -0,0 +1,45 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\config_override_test\ConfigOverriderLowPriority.
+ */
+
+namespace Drupal\config_override_test;
+
+use Drupal\Core\Config\ConfigFactoryOverrideInterface;
+
+/**
+ * Tests module overrides for configuration.
+ */
+class ConfigOverriderLowPriority implements ConfigFactoryOverrideInterface {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function loadOverrides($names) {
+    $overrides = array();
+    if (!empty($GLOBALS['config_test_run_module_overrides'])) {
+      if (in_array('system.site', $names)) {
+        $overrides = array('system.site' =>
+          array(
+            'name' => 'Should not apply because of higher priority listener',
+            // This override should apply because it is not overridden by the
+            // higher priority listener.
+            'slogan' => 'Yay for overrides!',
+          )
+        );
+      }
+    }
+    return $overrides;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getCacheSuffix() {
+    return 'ConfigOverriderLowPriority';
+  }
+
+}
+