diff -u b/core/lib/Drupal/Core/Config/Config.php b/core/lib/Drupal/Core/Config/Config.php
--- b/core/lib/Drupal/Core/Config/Config.php
+++ b/core/lib/Drupal/Core/Config/Config.php
@@ -205,7 +205,24 @@
    * {@inheritdoc}
    */
   public function save() {
-    $this->preSave();
+    // Validate the configuration object name before saving.
+    static::validateName($this->name);
+
+    // If there is a schema for this configuration object, cast all values to
+    // conform to the schema.
+    if ($this->typedConfigManager->hasConfigSchema($this->name)) {
+      // Ensure that the schema wrapper has the latest data.
+      $this->schemaWrapper = NULL;
+      foreach ($this->data as $key => $value) {
+        $this->data[$key] = $this->castValue($key, $value);
+      }
+    }
+    else {
+      foreach ($this->data as $key => $value) {
+        $this->validateValue($key, $value);
+      }
+    }
+
     $this->storage->write($this->name, $this->data);
     $this->isNew = FALSE;
     $this->eventDispatcher->dispatch(ConfigEvents::SAVE, new ConfigCrudEvent($this));
reverted:
--- b/core/lib/Drupal/Core/Config/InstallStorage.php
+++ a/core/lib/Drupal/Core/Config/InstallStorage.php
@@ -221,18 +221,4 @@
     $this->folders = NULL;
   }
 
-  /**
-   * {@inheritdoc}
-   */
-  public function getAllCollectionNames() {
-    $collections = array();
-    $folders = array_unique(array_values($this->getAllFolders()));
-    foreach ($folders as $directory) {
-      $collections = array_merge($collections, $this->getAllCollectionNamesHelper($directory));
-    }
-    $collections = array_unique($collections);
-    sort($collections);
-    return $collections;
-  }
-
 }
reverted:
--- b/core/lib/Drupal/Core/Config/StorableConfigBase.php
+++ a/core/lib/Drupal/Core/Config/StorableConfigBase.php
@@ -115,31 +115,6 @@
   }
 
   /**
-   * Ensures validity of the configuration using schema if available.
-   *
-   * If the configuration is invalid in any way exceptions are thrown.
-   */
-  protected function preSave() {
-    // Validate the configuration object name before saving.
-    static::validateName($this->name);
-
-    // If there is a schema for this configuration object, cast all values to
-    // conform to the schema.
-    if ($this->typedConfigManager->hasConfigSchema($this->name)) {
-      // Ensure that the schema wrapper has the latest data.
-      $this->schemaWrapper = NULL;
-      foreach ($this->data as $key => $value) {
-        $this->data[$key] = $this->castValue($key, $value);
-      }
-    }
-    else {
-      foreach ($this->data as $key => $value) {
-        $this->validateValue($key, $value);
-      }
-    }
-  }
-
-  /**
    * Gets the schema wrapper for the whole configuration object.
    *
    * The schema wrapper is dependent on the configuration name and the whole
reverted:
--- b/core/modules/config/lib/Drupal/config/Tests/ConfigSchemaTestBase.php
+++ a/core/modules/config/lib/Drupal/config/Tests/ConfigSchemaTestBase.php
@@ -9,7 +9,6 @@
 
 use Drupal\Core\Config\Schema\ArrayElement;
 use Drupal\Core\Config\Schema\Property;
-use Drupal\Core\Config\StorageInterface;
 use Drupal\Core\Config\TypedConfigManagerInterface;
 use Drupal\Core\TypedData\Type\BooleanInterface;
 use Drupal\Core\TypedData\Type\StringInterface;
@@ -55,19 +54,11 @@
    *   The configuration name.
    * @param array $config_data
    *   The configuration data.
-   * @param array $collection
-   *   The configuration collection.
    */
+  public function assertConfigSchema(TypedConfigManagerInterface $typed_config, $config_name, $config_data) {
-  public function assertConfigSchema(TypedConfigManagerInterface $typed_config, $config_name, $config_data, $collection = StorageInterface::DEFAULT_COLLECTION) {
     $this->configName = $config_name;
     if (!$typed_config->hasConfigSchema($config_name)) {
+      $this->fail(String::format('No schema for !config_name', array('!config_name' => $config_name)));
-      if ($collection != StorageInterface::DEFAULT_COLLECTION) {
-        $msg = 'No schema for !config_name in !collection collection';
-      }
-      else {
-        $msg = 'No schema for !config_name';
-      }
-      $this->fail(String::format($msg, array('!config_name' => $config_name, '!collection' => $collection)));
       return;
     }
     $definition = $typed_config->getDefinition($config_name);
@@ -77,13 +68,7 @@
       $this->checkValue($key, $value);
     }
     if ($this->configPass) {
+      $this->pass(String::format('Schema found for !config_name and values comply with schema.', array('!config_name' => $config_name)));
-      if ($collection != StorageInterface::DEFAULT_COLLECTION) {
-        $msg = 'Schema found for !config_name in !collection collection and values comply with schema.';
-      }
-      else {
-        $msg = 'Schema found for !config_name and values comply with schema.';
-      }
-      $this->pass(String::format($msg, array('!config_name' => $config_name, '!collection' => $collection)));
     }
   }
 
diff -u b/core/modules/config/lib/Drupal/config/Tests/DefaultConfigTest.php b/core/modules/config/lib/Drupal/config/Tests/DefaultConfigTest.php
--- b/core/modules/config/lib/Drupal/config/Tests/DefaultConfigTest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/DefaultConfigTest.php
@@ -9,7 +9,6 @@
 
 use Drupal\config_test\TestInstallStorage;
 use Drupal\Core\Config\InstallStorage;
-use Drupal\Core\Config\StorageInterface;
 use Drupal\Core\Config\TypedConfigManager;
 
 /**
@@ -51,27 +50,21 @@
     // every module, profile and theme.
     $default_config_storage = new TestInstallStorage();
 
-    $collections = $default_config_storage->getAllCollectionNames();
-    array_unshift($collections, StorageInterface::DEFAULT_COLLECTION);
-
-    foreach ($collections as $collection) {
-      $default_config_storage = $default_config_storage->createCollection($collection);
-      foreach ($default_config_storage->listAll() as $config_name) {
-        // @todo: remove once migration (https://drupal.org/node/2183957) schemas
-        // are in.
-        if (strpos($config_name, 'migrate.migration') === 0) {
-          continue;
-        }
-
-        // Skip files provided by the config_schema_test module since that module
-        // is explicitly for testing schema.
-        if (strpos($config_name, 'config_schema_test') === 0) {
-          continue;
-        }
+    foreach ($default_config_storage->listAll() as $config_name) {
+      // @todo: remove once migration (https://drupal.org/node/2183957) schemas
+      // are in.
+      if (strpos($config_name, 'migrate.migration') === 0) {
+        continue;
+      }
 
-        $data = $default_config_storage->read($config_name);
-        $this->assertConfigSchema($typed_config, $config_name, $data);
+      // Skip files provided by the config_schema_test module since that module
+      // is explicitly for testing schema.
+      if (strpos($config_name, 'config_schema_test') === 0) {
+        continue;
       }
+
+      $data = $default_config_storage->read($config_name);
+      $this->assertConfigSchema($typed_config, $config_name, $data);
     }
   }
 
diff -u b/core/modules/language/lib/Drupal/language/Config/LanguageConfigOverride.php b/core/modules/language/lib/Drupal/language/Config/LanguageConfigOverride.php
--- b/core/modules/language/lib/Drupal/language/Config/LanguageConfigOverride.php
+++ b/core/modules/language/lib/Drupal/language/Config/LanguageConfigOverride.php
@@ -37,7 +37,12 @@
    * {@inheritdoc}
    */
   public function save() {
-    $this->preSave();
+    // @todo Use configuration schema to validate.
+    //   https://drupal.org/node/2270399
+    // Perform basic data validation.
+    foreach ($this->data as $key => $value) {
+      $this->validateValue($key, $value);
+    }
     $this->storage->write($this->name, $this->data);
     $this->isNew = FALSE;
     $this->originalData = $this->data;
reverted:
--- /dev/null
+++ a/core/modules/tour/tests/tour_test/config/install/language.config.it.tour.tour.tour-test.yml
@@ -0,0 +1,5 @@
+label: Tour test italian
+tips:
+  tour-test-1:
+    label: La pioggia cade in spagna
+    body: Per lo più in pianura.
reverted:
--- b/core/modules/tour/tests/tour_test/config/install/language/it/tour.tour.tour-test.yml
+++ /dev/null
@@ -1,6 +0,0 @@
-label: Tour test italian
-tips:
-  tour-test-1:
-    plugin: text
-    label: 'La pioggia cade in spagna'
-    body: 'Per lo più in pianura.'