diff --git a/core/lib/Drupal/Core/Config/Config.php b/core/lib/Drupal/Core/Config/Config.php
index e000200..09b0a43 100644
--- a/core/lib/Drupal/Core/Config/Config.php
+++ b/core/lib/Drupal/Core/Config/Config.php
@@ -137,7 +137,7 @@ class Config extends DependencySerialization {
    * @param \Drupal\Core\Language\Language $language
    *   The language object used to override configuration data.
    */
-  public function __construct($name, StorageInterface $storage, EventDispatcherInterface $event_dispatcher, TypedConfigManager $typed_config, Language $language = NULL) {
+  public function __construct($name, StorageInterface $storage, EventDispatcherInterface $event_dispatcher, TypedConfigManagerInterface $typed_config, Language $language = NULL) {
     $this->name = $name;
     $this->storage = $storage;
     $this->eventDispatcher = $event_dispatcher;
@@ -201,13 +201,13 @@ public function setName($name) {
   public static function validateName($name) {
     // The name must be namespaced by owner.
     if (strpos($name, '.') === FALSE) {
-      throw new ConfigNameException(format_string('Missing namespace in Config object name @name.', array(
+      throw new ConfigNameException(String::format('Missing namespace in Config object name @name.', array(
         '@name' => $name,
       )));
     }
     // The name must be shorter than Config::MAX_NAME_LENGTH characters.
     if (strlen($name) > self::MAX_NAME_LENGTH) {
-      throw new ConfigNameException(format_string('Config object name @name exceeds maximum allowed length of @length characters.', array(
+      throw new ConfigNameException(String::format('Config object name @name exceeds maximum allowed length of @length characters.', array(
         '@name' => $name,
         '@length' => self::MAX_NAME_LENGTH,
       )));
@@ -216,7 +216,7 @@ public static function validateName($name) {
     // The name must not contain any of the following characters:
     // : ? * < > " ' / \
     if (preg_match('/[:?*<>"\'\/\\\\]/', $name)) {
-      throw new ConfigNameException(format_string('Invalid character in Config object name @name.', array(
+      throw new ConfigNameException(String::format('Invalid character in Config object name @name.', array(
         '@name' => $name,
       )));
     }
diff --git a/core/tests/Drupal/Tests/Core/Config/ConfigTest.php b/core/tests/Drupal/Tests/Core/Config/ConfigTest.php
new file mode 100644
index 0000000..feefaaa
--- /dev/null
+++ b/core/tests/Drupal/Tests/Core/Config/ConfigTest.php
@@ -0,0 +1,130 @@
+<?php
+
+namespace Drupal\Tests\Core\Config;
+
+use Drupal\Tests\UnitTestCase;
+use Drupal\Core\Config\Config;
+use Drupal\Component\Utility\String;
+
+/**
+ * Tests the Config.
+ *
+ * @group Drupal
+ * @group Config
+ *
+ * @see \Drupal\Core\Config\Config
+ */
+class ConfigTest extends UnitTestCase {
+
+  /**
+   * Config.
+   *
+   * @var \Drupal\Core\Config\Config
+   */
+  protected $config;
+
+  /**
+   * Storage.
+   * 
+   * @var \Drupal\Core\Config\StorageInterface
+   */
+  protected $storage;
+
+  /**
+   * Event Dispatcher.
+   * 
+   * @var \Symfony\Component\EventDispatcher\EventDispatcherInterface
+	 */
+  protected $event_dispatcher;
+
+  /**
+   * Typed Config.
+   * 
+   * @var \Drupal\Core\Config\TypedConfigManagerInterface
+   */
+  protected $typed_config;
+
+  /**
+   * Test Info.
+   */
+  public static function getInfo() {
+    return array(
+      'name' => 'Config test',
+      'description' => 'Tests Config.',
+      'group' => 'Configuration'
+    );
+  }
+
+  /**
+   * Setup.
+   */
+  public function setUp() {
+    $this->storage = $this->getMock('Drupal\Core\Config\StorageInterface');
+    $this->event_dispatcher = $this->getMock('Symfony\Component\EventDispatcher\EventDispatcherInterface');
+    $this->typed_config = $this->getMock('\Drupal\Core\Config\TypedConfigManagerInterface');
+    $this->config = new Config('configTest', $this->storage, $this->event_dispatcher, $this->typed_config);
+  }
+
+  /**
+   * Check that the config name is set correctly.
+   */
+  public function testSetName() {
+    // Valid name with dot.
+    $testName = 'test.name';
+
+    // Set the name.
+    $this->config->setName($testName);
+
+    // Check that the name has been set correctly.
+    $this->assertEquals($testName, $this->config->getName());
+
+    // Check that the name validates.
+    // Should throw \Drupal\Core\Config\ConfigNameException if invalid. 
+    $this->config->validateName($testName);
+  }
+
+  /**
+   * Checks that name validation exception are thrown.
+   * 
+   * @expectedException \Drupal\Core\Config\ConfigNameException
+   * @dataProvider validateNameProvider
+   */
+  public function testValidateNameException($name, $exception_message) {
+    $this->setExpectedException('\Drupal\Core\Config\ConfigNameException', $exception_message);
+    $this->config->validateName($name);
+  }
+
+  /**
+   * Provides data to test name validation.
+   */
+  public function validateNameProvider() {
+    $return = array(
+      // Name missing namespace (dot).
+      array(
+      	'MissingNamespace',
+      	String::format('Missing namespace in Config object name MissingNamespace.', array(
+      	  '@name' => 'MissingNamespace', 
+      	)),
+      ),
+      // Exceeds length (max length plus an extra dot).
+      array(
+        str_repeat('a', Config::MAX_NAME_LENGTH) . ".", 
+        String::format('Config object name @name exceeds maximum allowed length of @length characters.', array(
+      		'@name' => str_repeat('a', Config::MAX_NAME_LENGTH) . ".",
+        	'@length' => Config::MAX_NAME_LENGTH,
+        )),
+      ),      
+    );
+    // Name must not contain : ? * < > " ' / \
+    foreach (array(':', '?', '*', '<', '>', '"',"'",'/','\\') as $char) {
+      $name = 'name.' . $char;
+      $return[] = array(
+      	$name,
+        String::format('Invalid character in Config object name @name.', array(
+          '@name' => $name,
+        ))
+      );
+    }
+    return $return;
+  }
+}