diff --git a/core/lib/Drupal/Core/Config/ConfigFactoryOverrideBase.php b/core/lib/Drupal/Core/Config/ConfigFactoryOverrideBase.php
index 18d2ee8..09123e8 100644
--- a/core/lib/Drupal/Core/Config/ConfigFactoryOverrideBase.php
+++ b/core/lib/Drupal/Core/Config/ConfigFactoryOverrideBase.php
@@ -67,12 +67,12 @@ static function getSubscribedEvents() {
    */
   protected function filterOverride(Config $config, StorableConfigBase $override) {
     $override_data = $override->get();
-    $this->filterNestedArray($config->get(), $override_data);
+    $changed = $this->filterNestedArray($config->get(), $override_data);
     if (empty($override_data)) {
       // If no override values are left that would apply, remove the override.
       $override->delete();
     }
-    else {
+    elseif ($changed) {
       // Otherwise set the filtered override values back.
       $override->setData($override_data)->save();
     }
@@ -87,27 +87,32 @@ protected function filterOverride(Config $config, StorableConfigBase $override)
    *   Override data to filter.
    */
   protected function filterNestedArray(array $original_data, array &$override_data) {
+    $changed = FALSE;
     foreach ($override_data as $key => $value) {
       if (!isset($original_data[$key])) {
         // The original data is not there anymore, remove the override.
         unset($override_data[$key]);
+        $changed = TRUE;
       }
       elseif (is_array($override_data[$key])) {
         if (is_array($original_data[$key])) {
           // Do the filtering one level deeper.
-          $this->filterNestedArray($original_data[$key], $override_data[$key]);
+          $changed = $this->filterNestedArray($original_data[$key], $override_data[$key]);
           // If no overrides are left under this level, remove the level.
           if (empty($override_data[$key])) {
             unset($override_data[$key]);
+            $changed = TRUE;
           }
         }
         else {
           // The override is an array but the value is not, this will not go
           // well, remove the override.
           unset($override_data[$key]);
+          $changed = TRUE;
         }
       }
     }
+    return $changed;
   }
 
 }
diff --git a/core/modules/locale/src/Tests/LocaleConfigSubscriberTest.php b/core/modules/locale/src/Tests/LocaleConfigSubscriberTest.php
index d95458c..b358835 100644
--- a/core/modules/locale/src/Tests/LocaleConfigSubscriberTest.php
+++ b/core/modules/locale/src/Tests/LocaleConfigSubscriberTest.php
@@ -22,7 +22,7 @@ class LocaleConfigSubscriberTest extends KernelTestBase {
   /**
    * {@inheritdoc}
    */
-  public static $modules = ['language', 'locale', 'locale_test'];
+  public static $modules = ['language', 'locale'];
 
   /**
    * The configurable language manager used in this test.
@@ -53,31 +53,52 @@ class LocaleConfigSubscriberTest extends KernelTestBase {
   protected $localeConfigManager;
 
   /**
-   * The language code used in this test.
-   *
-   * @var string
-   */
-  protected $langcode = 'de';
-
-  /**
    * {@inheritdoc}
    */
   protected function setUp() {
     parent::setUp();
 
-    $this->languageManager = $this->container->get('language_manager');
+    $this->setUpDefaultLanguage();
+
+    $this->installSchema('locale', ['locales_source', 'locales_target', 'locales_location']);
+
+    $this->setupLanguages();
+
+    $this->enableModules(['locale_test']);
+    $this->installConfig(['locale_test']);
+    // Simulate this hook invoked which would happen if in a non-kernel test
+    // or normal environment.
+    locale_modules_installed(array('locale_test'));
+
     $this->configFactory = $this->container->get('config.factory');
     $this->stringStorage = $this->container->get('locale.storage');
     $this->localeConfigManager = $this->container->get('locale.config_manager');
+    $this->languageManager = $this->container->get('language_manager');
 
-    $this->installSchema('locale', ['locales_source', 'locales_target', 'locales_location']);
+    $this->setUpLocale();
+  }
 
-    $this->installConfig(['locale_test']);
-    ConfigurableLanguage::createFromLangcode($this->langcode)->save();
+  /**
+   * Sets up default language for this test.
+   */
+  protected function setUpDefaultLanguage() {
+    // Keep the default English.
+  }
+
+  /**
+   * Sets up languages needed for this test.
+   */
+  protected function setUpLanguages() {
+    ConfigurableLanguage::createFromLangcode('de')->save();
+  }
 
+  /**
+   * Sets up the locale storage strings to be in line with configuration.
+   */
+  protected function setUpLocale() {
     // Set up the locale database the same way we have in the config samples.
-    $this->setUpNoTranslation('locale_test.no_translation', 'test', 'Test');
-    $this->setUpTranslation('locale_test.translation', 'test', 'English test', 'German test');
+    $this->setUpNoTranslation('locale_test.no_translation', 'test', 'Test', 'de');
+    $this->setUpTranslation('locale_test.translation', 'test', 'English test', 'German test', 'de');
   }
 
   /**
@@ -86,8 +107,8 @@ protected function setUp() {
   public function testCreateTranslation() {
     $config_name = 'locale_test.no_translation';
 
-    $this->saveLanguageOverride($config_name, 'test', 'Test (German)');
-    $this->assertTranslation($config_name, 'Test (German)');
+    $this->saveLanguageOverride($config_name, 'test', 'Test (German)', 'de');
+    $this->assertTranslation($config_name, 'Test (German)', 'de');
   }
 
   /**
@@ -96,8 +117,8 @@ public function testCreateTranslation() {
   public function testLocaleCreateTranslation() {
     $config_name = 'locale_test.no_translation';
 
-    $this->saveLocaleTranslationData($config_name, 'test', 'Test', 'Test (German)');
-    $this->assertTranslation($config_name, 'Test (German)', FALSE);
+    $this->saveLocaleTranslationData($config_name, 'test', 'Test', 'Test (German)', 'de');
+    $this->assertTranslation($config_name, 'Test (German)', 'de', FALSE);
   }
 
   /**
@@ -106,8 +127,8 @@ public function testLocaleCreateTranslation() {
   public function testUpdateTranslation() {
     $config_name = 'locale_test.translation';
 
-    $this->saveLanguageOverride($config_name, 'test', 'Updated German test');
-    $this->assertTranslation($config_name, 'Updated German test');
+    $this->saveLanguageOverride($config_name, 'test', 'Updated German test', 'de');
+    $this->assertTranslation($config_name, 'Updated German test', 'de');
   }
 
   /**
@@ -116,8 +137,8 @@ public function testUpdateTranslation() {
   public function testLocaleUpdateTranslation() {
     $config_name = 'locale_test.translation';
 
-    $this->saveLocaleTranslationData($config_name, 'test', 'English test', 'Updated German test');
-    $this->assertTranslation($config_name, 'Updated German test', FALSE);
+    $this->saveLocaleTranslationData($config_name, 'test', 'English test', 'Updated German test', 'de');
+    $this->assertTranslation($config_name, 'Updated German test', 'de', FALSE);
   }
 
   /**
@@ -126,11 +147,11 @@ public function testLocaleUpdateTranslation() {
   public function testDeleteTranslation() {
     $config_name = 'locale_test.translation';
 
-    $this->deleteLanguageOverride($config_name, 'test', 'English test');
+    $this->deleteLanguageOverride($config_name, 'test', 'English test', 'de');
     // Instead of deleting the translation, we need to keep a translation with
     // the source value and mark it as customized to prevent the deletion being
     // reverted by importing community translations.
-    $this->assertTranslation($config_name, 'English test');
+    $this->assertTranslation($config_name, 'English test', 'de');
   }
 
   /**
@@ -139,8 +160,8 @@ public function testDeleteTranslation() {
   public function testLocaleDeleteTranslation() {
     $config_name = 'locale_test.translation';
 
-    $this->deleteLocaleTranslationData($config_name, 'test', 'English test');
-    $this->assertNoTranslation($config_name);
+    $this->deleteLocaleTranslationData($config_name, 'test', 'English test', 'de');
+    $this->assertNoTranslation($config_name, 'de');
   }
 
   /**
@@ -157,14 +178,13 @@ public function testLocaleDeleteTranslation() {
    *   The configuration key.
    * @param string $source
    *   The source string.
+   * @param string $langcode
+   *   The language code.
    */
-  protected function setUpNoTranslation($config_name, $key, $source) {
-    $this->localeConfigManager->updateConfigTranslations(array($config_name), array($this->langcode));
-    $this->languageManager
-      ->setConfigOverrideLanguage(ConfigurableLanguage::load($this->langcode));
-
-    $this->assertConfigValue($config_name, $key, $source);
-    $this->assertNoTranslation($config_name);
+  protected function setUpNoTranslation($config_name, $key, $source, $langcode) {
+    $this->localeConfigManager->updateConfigTranslations(array($config_name), array($langcode));
+    $this->assertNoConfigOverride($config_name, $key, $source, $langcode);
+    $this->assertNoTranslation($config_name, $langcode);
   }
 
 
@@ -184,23 +204,33 @@ protected function setUpNoTranslation($config_name, $key, $source) {
    *   The source string.
    * @param string $translation
    *   The translation string.
+   * @param string $langcode
+   *   The language code.
+   * @param bool $is_active
+   *   Whether the update will affect the active configuration.
    */
-  protected function setUpTranslation($config_name, $key, $source, $translation) {
+  protected function setUpTranslation($config_name, $key, $source, $translation, $langcode, $is_active = FALSE) {
     // Create source and translation strings for the configuration value and add
     // the configuration name as a location. This would be performed by
     // locale_translate_batch_import() invoking
     // LocaleConfigManager::updateConfigTranslations() normally.
     $this->localeConfigManager->reset();
     $this->localeConfigManager
-      ->getStringTranslation($config_name, $this->langcode, $source, '')
+      ->getStringTranslation($config_name, $langcode, $source, '')
       ->setString($translation)
       ->setCustomized(FALSE)
       ->save();
-    $this->languageManager
-      ->setConfigOverrideLanguage(ConfigurableLanguage::load($this->langcode));
+    $this->configFactory->reset($config_name);
+    $this->localeConfigManager->reset();
+    $this->localeConfigManager->updateConfigTranslations(array($config_name), array($langcode));
 
-    $this->assertConfigValue($config_name, $key, $translation);
-    $this->assertTranslation($config_name, $translation, FALSE);
+    if ($is_active) {
+      $this->assertActiveConfig($config_name, $key, $translation, $langcode);
+    }
+    else {
+      $this->assertConfigOverride($config_name, $key, $translation, $langcode);
+    }
+    $this->assertTranslation($config_name, $translation, $langcode, FALSE);
   }
 
   /**
@@ -218,16 +248,18 @@ protected function setUpTranslation($config_name, $key, $source, $translation) {
    *   The configuration key.
    * @param string $value
    *   The configuration value to save.
+   * @param string $langcode
+   *   The language code.
    */
-  protected function saveLanguageOverride($config_name, $key, $value) {
+  protected function saveLanguageOverride($config_name, $key, $value, $langcode) {
     $translation_override = $this->languageManager
-      ->getLanguageConfigOverride($this->langcode, $config_name);
+      ->getLanguageConfigOverride($langcode, $config_name);
     $translation_override
       ->set($key, $value)
       ->save();
     $this->configFactory->reset($config_name);
 
-    $this->assertConfigValue($config_name, $key, $value);
+    $this->assertConfigOverride($config_name, $key, $value, $langcode);
   }
 
   /**
@@ -245,17 +277,27 @@ protected function saveLanguageOverride($config_name, $key, $value) {
    *   The configuration key.
    * @param string $value
    *   The configuration value to save.
+   * @param string $langcode
+   *   The language code.
+   * @param bool $is_active
+   *   Whether the update will affect the active configuration.
    */
-  protected function saveLocaleTranslationData($config_name, $key, $source, $translation) {
+  protected function saveLocaleTranslationData($config_name, $key, $source, $translation, $langcode, $is_active = FALSE) {
+    $this->localeConfigManager->reset();
     $this->localeConfigManager
-      ->getStringTranslation($config_name, $this->langcode, $source, '')
+      ->getStringTranslation($config_name, $langcode, $source, '')
       ->setString($translation)
       ->save();
     $this->localeConfigManager->reset();
-    $this->localeConfigManager->updateConfigTranslations(array($config_name), array($this->langcode));
+    $this->localeConfigManager->updateConfigTranslations(array($config_name), array($langcode));
     $this->configFactory->reset($config_name);
 
-    $this->assertConfigValue($config_name, $key, $translation);
+    if ($is_active) {
+      $this->assertActiveConfig($config_name, $key, $translation, $langcode);
+    }
+    else {
+      $this->assertConfigOverride($config_name, $key, $translation, $langcode);
+    }
   }
 
   /**
@@ -274,16 +316,18 @@ protected function saveLocaleTranslationData($config_name, $key, $source, $trans
    * @param string $source_value
    *   The source configuration value to verify the correct value is returned
    *   from the configuration factory after the deletion.
+   * @param string $langcode
+   *   The language code.
    */
-  protected function deleteLanguageOverride($config_name, $key, $source_value) {
+  protected function deleteLanguageOverride($config_name, $key, $source_value, $langcode) {
     $translation_override = $this->languageManager
-      ->getLanguageConfigOverride($this->langcode, $config_name);
+      ->getLanguageConfigOverride($langcode, $config_name);
     $translation_override
       ->clear($key)
       ->save();
     $this->configFactory->reset($config_name);
 
-    $this->assertConfigValue($config_name, $key, $source_value);
+    $this->assertNoConfigOverride($config_name, $key, $source_value, $langcode);
   }
 
   /**
@@ -302,35 +346,78 @@ protected function deleteLanguageOverride($config_name, $key, $source_value) {
    * @param string $source_value
    *   The source configuration value to verify the correct value is returned
    *   from the configuration factory after the deletion.
+   * @param string $langcode
+   *   The language code.
    */
-  protected function deleteLocaleTranslationData($config_name, $key, $source_value) {
+  protected function deleteLocaleTranslationData($config_name, $key, $source_value, $langcode) {
     $this->localeConfigManager
-      ->getStringTranslation($config_name, $this->langcode, $source_value, '')
+      ->getStringTranslation($config_name, $langcode, $source_value, '')
       ->delete();
     $this->localeConfigManager->reset();
-    $this->localeConfigManager->updateConfigTranslations(array($config_name), array($this->langcode));
+    $this->localeConfigManager->updateConfigTranslations(array($config_name), array($langcode));
     $this->configFactory->reset($config_name);
 
-    $this->assertConfigValue($config_name, $key, $source_value);
+    $this->assertNoConfigOverride($config_name, $key, $source_value, $langcode);
+  }
+
+  /**
+   * Ensures configuration override is not present anymore.
+   *
+   * @param string $config_name
+   *   The configuration name.
+   * @param string $langcode
+   *   The language code.
+   *
+   * @return bool
+   *   TRUE if the assertion succeeded, FALSE otherwise.
+   */
+  protected function assertNoConfigOverride($config_name, $langcode) {
+    $config_langcode = $this->configFactory->getEditable($config_name)->get('langcode');
+    $override = $this->languageManager->getLanguageConfigOverride($langcode, $config_name);
+    return $this->assertNotEqual($config_langcode, $langcode) && $this->assertEqual($override->isNew(), TRUE);
+  }
+
+  /**
+   * Ensures configuration was saved correctly.
+   *
+   * @param string $config_name
+   *   The configuration name.
+   * @param string $key
+   *   The configuration key.
+   * @param string $value
+   *   The configuration value.
+   * @param string $langcode
+   *   The language code.
+   *
+   * @return bool
+   *   TRUE if the assertion succeeded, FALSE otherwise.
+   */
+  protected function assertConfigOverride($config_name, $key, $value, $langcode) {
+    $config_langcode = $this->configFactory->getEditable($config_name)->get('langcode');
+    $override = $this->languageManager->getLanguageConfigOverride($langcode, $config_name);
+    return $this->assertNotEqual($config_langcode, $langcode) && $this->assertEqual($override->get($key), $value);
   }
 
   /**
    * Ensures configuration was saved correctly.
    *
-   * @param $config_name
+   * @param string $config_name
    *   The configuration name.
-   * @param $key
+   * @param string $key
    *   The configuration key.
-   * @param $value
+   * @param string $value
    *   The configuration value.
+   * @param string $langcode
+   *   The language code.
    *
    * @return bool
    *   TRUE if the assertion succeeded, FALSE otherwise.
    */
-  protected function assertConfigValue($config_name, $key, $value) {
-    // Make sure the configuration was translated correctly.
-    $translation_config = $this->configFactory->get($config_name);
-    return $this->assertIdentical($value, $translation_config->get($key));
+  protected function assertActiveConfig($config_name, $key, $value, $langcode) {
+    $config = $this->configFactory->getEditable($config_name);
+    return
+      $this->assertEqual($config->get('langcode'), $langcode) &&
+      $this->assertIdentical($config->get($key), $value);
   }
 
   /**
@@ -338,15 +425,17 @@ protected function assertConfigValue($config_name, $key, $value) {
    *
    * @param string $config_name
    *   The configuration name.
+   * @param string $langcode
+   *   The language code.
    *
    * @return bool
    *   TRUE if the assertion succeeded, FALSE otherwise.
    */
-  protected function assertNoTranslation($config_name) {
+  protected function assertNoTranslation($config_name, $langcode) {
     $strings = $this->stringStorage->getTranslations([
       'type' => 'configuration',
       'name' => $config_name,
-      'language' => $this->langcode,
+      'language' => $langcode,
       'translated' => TRUE,
     ]);
     return $this->assertIdentical([], $strings);
@@ -359,6 +448,8 @@ protected function assertNoTranslation($config_name) {
    *   The configuration name.
    * @param string $translation
    *   The translation.
+   * @param string $langcode
+   *   The language code.
    * @param bool $customized
    *   Whether or not the string should be asserted to be customized or not
    *   customized.
@@ -366,12 +457,12 @@ protected function assertNoTranslation($config_name) {
    * @return bool
    *   TRUE if the assertion succeeded, FALSE otherwise.
    */
-  protected function assertTranslation($config_name, $translation, $customized = TRUE) {
+  protected function assertTranslation($config_name, $translation, $langcode, $customized = TRUE) {
     // Make sure a string exists.
     $strings = $this->stringStorage->getTranslations([
       'type' => 'configuration',
       'name' => $config_name,
-      'language' => $this->langcode,
+      'language' => $langcode,
       'translated' => TRUE,
     ]);
     $pass = $this->assertIdentical(1, count($strings));
diff --git a/core/modules/locale/tests/modules/locale_test/config/schema/locale_test.schema.yml b/core/modules/locale/tests/modules/locale_test/config/schema/locale_test.schema.yml
index 5e7e056..daf3391 100644
--- a/core/modules/locale/tests/modules/locale_test/config/schema/locale_test.schema.yml
+++ b/core/modules/locale/tests/modules/locale_test/config/schema/locale_test.schema.yml
@@ -9,6 +9,8 @@ locale_test.no_translation:
       label: 'Test'
       # See \Drupal\locale\Tests\LocaleConfigSubscriberTest
       translatable: true
+    langcode:
+      type: string
 
 locale_test.translation:
   type: mapping
@@ -19,3 +21,5 @@ locale_test.translation:
       label: 'Test'
       # See \Drupal\locale\Tests\LocaleConfigSubscriberTest
       translatable: true
+    langcode:
+      type: string
diff --git a/core/modules/simpletest/src/KernelTestBase.php b/core/modules/simpletest/src/KernelTestBase.php
index 89930ad..f6c23b6 100644
--- a/core/modules/simpletest/src/KernelTestBase.php
+++ b/core/modules/simpletest/src/KernelTestBase.php
@@ -290,7 +290,7 @@ public function containerBuild(ContainerBuilder $container) {
     $this->container = $container;
 
     // Set the default language on the minimal container.
-    $this->container->setParameter('language.default_values', Language::$defaultValues);
+    $this->container->setParameter('language.default_values', $this->defaultLanguageData());
 
     $container->register('lock', 'Drupal\Core\Lock\NullLockBackend');
     $container->register('cache_factory', 'Drupal\Core\Cache\MemoryBackendFactory');
@@ -359,6 +359,16 @@ public function containerBuild(ContainerBuilder $container) {
   }
 
   /**
+   * Provides the data for setting the default language on the container.
+   *
+   * @return array
+   *   The data array for the default language.
+   */
+  protected function defaultLanguageData() {
+    return Language::$defaultValues;
+  }
+
+  /**
    * Installs default configuration for a given list of modules.
    *
    * @param array $modules
diff --git a/core/modules/locale/src/Tests/LocaleConfigSubscriberForeignTest.php b/core/modules/locale/src/Tests/LocaleConfigSubscriberForeignTest.php
new file mode 100644
index 0000000..289333e
--- /dev/null
+++ b/core/modules/locale/src/Tests/LocaleConfigSubscriberForeignTest.php
@@ -0,0 +1,170 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\locale\Tests\LocaleConfigSubscriberForeignTest.
+ */
+
+namespace Drupal\locale\Tests;
+
+use Drupal\Core\Language\Language;
+use Drupal\language\Entity\ConfigurableLanguage;
+
+/**
+ * Tests default configuration handling with a foreign default language.
+ *
+ * @group locale
+ */
+class LocaleConfigSubscriberForeignTest extends LocaleConfigSubscriberTest {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function defaultLanguageData() {
+    $data = Language::$defaultValues;
+    $data['id'] = 'hu';
+    $data['name'] = 'Hungarian';
+    return $data;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUpLanguages() {
+    parent::setUpLanguages();
+    ConfigurableLanguage::createFromLangcode('hu')->save();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUpLocale() {
+    parent::setUpLocale();
+    $this->setUpTranslation('locale_test.translation', 'test', 'English test', 'Hungarian test', 'hu', TRUE);
+  }
+
+  /**
+   * Tests that the language of default configuration was updated.
+   */
+  public function testDefaultConfigLanguage() {
+    $this->assertEqual('hu', $this->configFactory->getEditable('locale_test.no_translation')->get('langcode'));
+    $this->assertEqual('hu', $this->configFactory->getEditable('locale_test.translation')->get('langcode'));
+    $this->assertEqual($this->configFactory->getEditable('locale_test.translation')->get('test'), 'Hungarian test');
+  }
+
+  /**
+   * Tests creating translations of shipped configuration.
+   */
+  public function testCreateActiveTranslation() {
+    $config_name = 'locale_test.no_translation';
+    $this->saveLanguageActive($config_name, 'test', 'Test (Hungarian)', 'hu');
+    $this->assertTranslation($config_name, 'Test (Hungarian)', 'hu');
+  }
+
+  /**
+   * Tests importing community translations of shipped configuration.
+   */
+  public function testLocaleCreateActiveTranslation() {
+    $config_name = 'locale_test.no_translation';
+    $this->saveLocaleTranslationData($config_name, 'test', 'Test', 'Test (Hungarian)', 'hu', TRUE);
+    $this->assertTranslation($config_name, 'Test (Hungarian)', 'hu', FALSE);
+  }
+
+  /**
+   * Tests updating translations of shipped configuration.
+   */
+  public function testUpdateActiveTranslation() {
+    $config_name = 'locale_test.translation';
+    $this->saveLanguageActive($config_name, 'test', 'Updated Hungarian test', 'hu');
+    $this->assertTranslation($config_name, 'Updated Hungarian test', 'hu');
+  }
+
+  /**
+   * Tests updating community translations of shipped configuration.
+   */
+  public function testLocaleUpdateActiveTranslation() {
+    $config_name = 'locale_test.translation';
+    $this->saveLocaleTranslationData($config_name, 'test', 'English test', 'Updated Hungarian test', 'hu', TRUE);
+    $this->assertTranslation($config_name, 'Updated Hungarian test', 'hu', FALSE);
+  }
+
+  /**
+   * @inheritdoc
+   */
+  public function testDeleteTranslation() {
+    $config_name = 'locale_test.translation';
+    $this->deleteLanguageOverride($config_name, 'test', 'English test', 'de');
+    // The German translation in this case will be forced to the Hungarian
+    // source so its not overwritten with locale data later.
+    $this->assertTranslation($config_name, 'Hungarian test', 'de');
+  }
+
+  /**
+   * Tests deleting translations of shipped configuration.
+   */
+  public function testDeleteActiveTranslation() {
+    $config_name = 'locale_test.translation';
+    $this->configFactory->getEditable($config_name)->delete();
+    // Deleting active configuration should not change the locale translation.
+    $this->assertTranslation($config_name, 'Hungarian test', 'hu', FALSE);
+  }
+
+  /**
+   * Tests deleting community translations of shipped configuration.
+   */
+  public function testLocaleDeleteActiveTranslation() {
+    $config_name = 'locale_test.translation';
+    $this->deleteLocaleTranslationData($config_name, 'test', 'English test', 'hu');
+    // Deleting the locale translation should not change active config.
+    $this->assertEqual($this->configFactory->getEditable($config_name)->get('test'), 'Hungarian test');
+  }
+
+  /**
+   * Tests that adding English creates a translation override.
+   */
+  public function testEnglish() {
+    $config_name = 'locale_test.translation';
+    ConfigurableLanguage::createFromLangcode('en')->save();
+    // Adding a language on the UI would normally call updateConfigTranslations.
+    $this->localeConfigManager->updateConfigTranslations(array($config_name), array('en'));
+    $this->assertConfigOverride($config_name, 'test', 'English test', 'en');
+
+    $this->configFactory->getEditable('locale.settings')->set('translate_english', TRUE)->save();
+    $this->saveLocaleTranslationData($config_name, 'test', 'English test', 'Updated English test', 'en');
+    $this->assertTranslation($config_name, 'Updated English test', 'en', FALSE);
+
+    $this->saveLanguageOverride($config_name, 'test', 'Updated English', 'en');
+    $this->assertTranslation($config_name, 'Updated English', 'en');
+
+    $this->deleteLocaleTranslationData($config_name, 'test', 'English test', 'en');
+    $this->assertNoConfigOverride($config_name, 'en');
+  }
+
+  /**
+   * Saves a language override.
+   *
+   * This will invoke LocaleConfigSubscriber through the event dispatcher. To
+   * make sure the configuration was persisted correctly, the configuration
+   * value is checked. Because LocaleConfigSubscriber temporarily disables the
+   * override state of the configuration factory we check that the correct value
+   * is restored afterwards.
+   *
+   * @param string $config_name
+   *   The configuration name.
+   * @param string $key
+   *   The configuration key.
+   * @param string $value
+   *   The configuration value to save.
+   * @param string $langcode
+   *   The language code.
+   */
+  protected function saveLanguageActive($config_name, $key, $value, $langcode) {
+    $this
+      ->configFactory
+      ->getEditable($config_name)
+      ->set($key, $value)
+      ->save();
+    $this->assertActiveConfig($config_name, $key, $value, $langcode);
+  }
+
+}