diff --git a/core/core.services.yml b/core/core.services.yml
index 3a90788..2c882c7 100644
--- a/core/core.services.yml
+++ b/core/core.services.yml
@@ -450,7 +450,7 @@ services:
       - [setCurrentUser, ['@?current_user']]
   access_manager:
     class: Drupal\Core\Access\AccessManager
-    arguments: ['@router.route_provider', '@url_generator', '@route_enhancer.param_conversion']
+    arguments: ['@router.route_provider', '@url_generator', '@paramconverter_manager']
     calls:
       - [setContainer, ['@service_container']]
       - [setRequest, ['@?request']]
diff --git a/core/lib/Drupal/Core/Access/AccessManager.php b/core/lib/Drupal/Core/Access/AccessManager.php
index c6b5155..42fc39a 100644
--- a/core/lib/Drupal/Core/Access/AccessManager.php
+++ b/core/lib/Drupal/Core/Access/AccessManager.php
@@ -7,19 +7,17 @@
 
 namespace Drupal\Core\Access;
 
-use Drupal\Core\ParamConverter\ParamConverterManager;
+use Drupal\Core\ParamConverter\ParamConverterManagerInterface;
 use Drupal\Core\ParamConverter\ParamNotConvertedException;
 use Drupal\Core\Routing\Access\AccessInterface as RoutingAccessInterface;
 use Drupal\Core\Routing\RequestHelper;
 use Drupal\Core\Routing\RouteProviderInterface;
 use Drupal\Core\Session\AccountInterface;
-use Symfony\Cmf\Component\Routing\Enhancer\RouteEnhancerInterface;
 use Symfony\Component\Routing\Generator\UrlGeneratorInterface;
 use Symfony\Component\Routing\RouteCollection;
 use Symfony\Component\Routing\Route;
 use Symfony\Component\DependencyInjection\ContainerAware;
 use Symfony\Component\HttpFoundation\Request;
-use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
 use Symfony\Component\Routing\Exception\RouteNotFoundException;
 use Symfony\Cmf\Component\Routing\RouteObjectInterface;
 
@@ -73,11 +71,11 @@ class AccessManager extends ContainerAware {
   protected $urlGenerator;
 
   /**
-   * The route enhancer.
+   * The paramconverter manager.
    *
-   * @var \Symfony\Cmf\Component\Routing\Enhancer\RouteEnhancerInterface
+   * @var \Drupal\Core\ParamConverter\ParamConverterManagerInterface
    */
-  protected $routeEnhancer;
+  protected $paramConverterManager;
 
   /**
    * A request object.
@@ -93,13 +91,13 @@ class AccessManager extends ContainerAware {
    *   The route provider.
    * @param \Symfony\Component\Routing\Generator\UrlGeneratorInterface $url_generator
    *   The url generator.
-   * @param \Symfony\Cmf\Component\Routing\Enhancer\RouteEnhancerInterface $route_enhancer
-   *   The route enhancer.
+   * @param \Drupal\Core\ParamConverter\ParamConverterManagerInterface $paramconverter_manager
+   *   The param converter manager.
    */
-  public function __construct(RouteProviderInterface $route_provider, UrlGeneratorInterface $url_generator, RouteEnhancerInterface $route_enhancer) {
+  public function __construct(RouteProviderInterface $route_provider, UrlGeneratorInterface $url_generator, ParamConverterManagerInterface $paramconverter_manager) {
     $this->routeProvider = $route_provider;
     $this->urlGenerator = $url_generator;
-    $this->routeEnhancer = $route_enhancer;
+    $this->paramConverterManager = $paramconverter_manager;
   }
 
   /**
@@ -204,7 +202,7 @@ public function checkNamedRoute($route_name, array $parameters = array(), Accoun
         $defaults = $parameters + $route->getDefaults();
         $route_request = RequestHelper::duplicate($this->request, $this->urlGenerator->generate($route_name, $defaults));
         $defaults[RouteObjectInterface::ROUTE_OBJECT] = $route;
-        $route_request->attributes->add($this->routeEnhancer->enhance($defaults, $route_request));
+        $route_request->attributes->add($this->paramConverterManager->convert($defaults, $route_request));
       }
       return $this->check($route, $route_request, $account);
     }
diff --git a/core/lib/Drupal/Core/EventSubscriber/ParamConverterSubscriber.php b/core/lib/Drupal/Core/EventSubscriber/ParamConverterSubscriber.php
index 7d385f5..b89e9ff 100644
--- a/core/lib/Drupal/Core/EventSubscriber/ParamConverterSubscriber.php
+++ b/core/lib/Drupal/Core/EventSubscriber/ParamConverterSubscriber.php
@@ -7,7 +7,7 @@
 
 namespace Drupal\Core\EventSubscriber;
 
-use Drupal\Core\ParamConverter\ParamConverterManager;
+use Drupal\Core\ParamConverter\ParamConverterManagerInterface;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 use Drupal\Core\Routing\RoutingEvents;
 use Drupal\Core\Routing\RouteBuildEvent;
@@ -20,18 +20,18 @@ class ParamConverterSubscriber implements EventSubscriberInterface {
   /**
    * The parameter converter manager.
    *
-   * @var \Drupal\Core\ParamConverter\ParamConverterManager
+   * @var \Drupal\Core\ParamConverter\ParamConverterManagerInterface
    */
   protected $paramConverterManager;
 
   /**
    * Constructs a new ParamConverterSubscriber.
    *
-   * @param \Drupal\Core\ParamConverter\ParamConverterManager $param_converter_manager
+   * @param \Drupal\Core\ParamConverter\ParamConverterManagerInterface $param_converter_manager
    *   The parameter converter manager that will be responsible for upcasting
    *   request attributes.
    */
-  public function __construct(ParamConverterManager $param_converter_manager) {
+  public function __construct(ParamConverterManagerInterface $param_converter_manager) {
     $this->paramConverterManager = $param_converter_manager;
   }
 
diff --git a/core/lib/Drupal/Core/EventSubscriber/RouterListener.php b/core/lib/Drupal/Core/EventSubscriber/RouterListener.php
index f3d76ca..0c730eb 100644
--- a/core/lib/Drupal/Core/EventSubscriber/RouterListener.php
+++ b/core/lib/Drupal/Core/EventSubscriber/RouterListener.php
@@ -21,11 +21,13 @@ class RouterListener extends SymfonyRouterListener {
    * {@inheritdoc}
    */
   public function onKernelRequest(GetResponseEvent $event) {
+    // Catch failed parameter conversions and throw a 404 instead. This cannot
+    // be done on the router level as it does not always deal with HTTP.
     try {
       parent::onKernelRequest($event);
     }
     catch (ParamNotConvertedException $e) {
-      throw new NotFoundHttpException();
+      throw new NotFoundHttpException('', $e);
     }
   }
 
diff --git a/core/lib/Drupal/Core/ParamConverter/ParamConverterManager.php b/core/lib/Drupal/Core/ParamConverter/ParamConverterManager.php
index 8061522..23d0686 100644
--- a/core/lib/Drupal/Core/ParamConverter/ParamConverterManager.php
+++ b/core/lib/Drupal/Core/ParamConverter/ParamConverterManager.php
@@ -8,7 +8,9 @@
 namespace Drupal\Core\ParamConverter;
 
 use Symfony\Component\DependencyInjection\ContainerAware;
+use Symfony\Cmf\Component\Routing\RouteObjectInterface;
 use Symfony\Component\Routing\RouteCollection;
+use Symfony\Component\HttpFoundation\Request;
 
 /**
  * Manages converter services for converting request parameters to full objects.
@@ -16,7 +18,7 @@
  * A typical use case for this would be upcasting (converting) a node id to a
  * node entity.
  */
-class ParamConverterManager extends ContainerAware {
+class ParamConverterManager extends ContainerAware implements ParamConverterManagerInterface {
 
   /**
    * An array of registered converter service ids.
@@ -40,15 +42,7 @@ class ParamConverterManager extends ContainerAware {
   protected $converters = array();
 
   /**
-   * Registers a parameter converter with the manager.
-   *
-   * @param string $converter
-   *   The parameter converter service id to register.
-   * @param int $priority
-   *   (optional) The priority of the converter. Defaults to 0.
-   *
-   * @return \Drupal\Core\ParamConverter\ParamConverterManager
-   *   The called object for chaining.
+   * {@inheritdoc}
    */
   public function addConverter($converter, $priority = 0) {
     if (empty($this->converterIds[$priority])) {
@@ -60,10 +54,7 @@ public function addConverter($converter, $priority = 0) {
   }
 
   /**
-   * Sorts the converter service ids and flattens them.
-   *
-   * @return array
-   *   The sorted parameter converter service ids.
+   * {@inheritdoc}
    */
   public function getConverterIds() {
     if (!isset($this->sortedConverterIds)) {
@@ -77,16 +68,7 @@ public function getConverterIds() {
   }
 
   /**
-   * Lazy-loads converter services.
-   *
-   * @param string $converter
-   *   The service id of converter service to load.
-   *
-   * @return \Drupal\Core\ParamConverter\ParamConverterInterface
-   *   The loaded converter service identified by the given service id.
-   *
-   * @throws \InvalidArgumentException
-   *   If the given service id is not a registered converter.
+   * {@inheritdoc}
    */
   public function getConverter($converter) {
     if (isset($this->converters[$converter])) {
@@ -99,10 +81,7 @@ public function getConverter($converter) {
   }
 
   /**
-   * Saves a list of applicable converters to each route.
-   *
-   * @param \Symfony\Component\Routing\RouteCollection $routes
-   *   A collection of routes to apply converters to.
+   * {@inheritdoc}
    */
   public function setRouteParameterConverters(RouteCollection $routes) {
     foreach ($routes->all() as $route) {
@@ -131,5 +110,40 @@ public function setRouteParameterConverters(RouteCollection $routes) {
     }
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function convert(array $defaults, Request $request) {
+    /** @var $route \Symfony\Component\Routing\Route */
+    $route = $defaults[RouteObjectInterface::ROUTE_OBJECT];
+
+    // Skip this enhancer if there are no parameter definitions.
+    if (!$parameters = $route->getOption('parameters')) {
+      return $defaults;
+    }
+
+    // Invoke the registered converter for each parameter.
+    foreach ($parameters as $name => $definition) {
+      if (!isset($defaults[$name])) {
+        // Do not try to convert anything that is already set to NULL.
+        continue;
+      }
+
+      if (!isset($definition['converter'])) {
+        // Continue if no converter has been specified.
+        continue;
+      }
+
+      // If a converter returns NULL it means that the parameter could not be
+      // converted.
+      $defaults[$name] = $this->getConverter($definition['converter'])->convert($defaults[$name], $definition, $name, $defaults, $request);
+      if (!isset($defaults[$name])) {
+        throw new ParamNotConvertedException(sprintf('The "%s" parameter was not converted for the path "%s"', $name, $route->getPath()));
+      }
+    }
+
+    return $defaults;
+  }
+
 }
 
diff --git a/core/lib/Drupal/Core/ParamConverter/ParamConverterManagerInterface.php b/core/lib/Drupal/Core/ParamConverter/ParamConverterManagerInterface.php
new file mode 100644
index 0000000..8240e62
--- /dev/null
+++ b/core/lib/Drupal/Core/ParamConverter/ParamConverterManagerInterface.php
@@ -0,0 +1,77 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\ParamConverter\ParamConverterManagerInterface.
+ */
+
+namespace Drupal\Core\ParamConverter;
+
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\Routing\RouteCollection;
+
+/**
+ * Provides an interface for a parameter converter manager.
+ */
+interface ParamConverterManagerInterface {
+
+  /**
+   * Registers a parameter converter with the manager.
+   *
+   * @param string $converter
+   *   The parameter converter service id to register.
+   * @param int $priority
+   *   (optional) The priority of the converter. Defaults to 0.
+   *
+   * @return $this
+   */
+  public function addConverter($converter, $priority = 0);
+
+  /**
+   * Sorts the converter service ids and flattens them.
+   *
+   * @return array
+   *   The sorted parameter converter service ids.
+   */
+    public function getConverterIds();
+
+  /**
+   * Lazy-loads converter services.
+   *
+   * @param string $converter
+   *   The service id of converter service to load.
+   *
+   * @return \Drupal\Core\ParamConverter\ParamConverterInterface
+   *   The loaded converter service identified by the given service id.
+   *
+   * @throws \InvalidArgumentException
+   *   If the given service id is not a registered converter.
+   */
+  public function getConverter($converter);
+
+  /**
+   * Saves a list of applicable converters to each route.
+   *
+   * @param \Symfony\Component\Routing\RouteCollection $routes
+   *   A collection of routes to apply converters to.
+   */
+  public function setRouteParameterConverters(RouteCollection $routes);
+
+  /**
+   * Invokes the registered converter for each defined parameter on a route.
+   *
+   * @param array $defaults
+   *   The route defaults array.
+   * @param \Symfony\Component\HttpFoundation\Request $request
+   *   The current request.
+   *
+   * @throws \Drupal\Core\ParamConverter\ParamNotConvertedException
+   *   If one of the assigned converters returned NULL because the given
+   *   variable could not be converted.
+   *
+   * @return array
+   *   The modified defaults.
+   */
+  public function convert(array $defaults, Request $request);
+
+}
diff --git a/core/lib/Drupal/Core/Routing/Enhancer/ParamConversionEnhancer.php b/core/lib/Drupal/Core/Routing/Enhancer/ParamConversionEnhancer.php
index 55b4392..742d940 100644
--- a/core/lib/Drupal/Core/Routing/Enhancer/ParamConversionEnhancer.php
+++ b/core/lib/Drupal/Core/Routing/Enhancer/ParamConversionEnhancer.php
@@ -7,8 +7,7 @@
 
 namespace Drupal\Core\Routing\Enhancer;
 
-use Drupal\Core\ParamConverter\ParamConverterManager;
-use Drupal\Core\ParamConverter\ParamNotConvertedException;
+use Drupal\Core\ParamConverter\ParamConverterManagerInterface;
 use Symfony\Cmf\Component\Routing\Enhancer\RouteEnhancerInterface;
 use Symfony\Cmf\Component\Routing\RouteObjectInterface;
 use Symfony\Component\HttpFoundation\ParameterBag;
@@ -20,14 +19,14 @@
 class ParamConversionEnhancer implements RouteEnhancerInterface {
 
   /**
-   * @var \Drupal\Core\ParamConverter\ParamConverterManager
+   * @var \Drupal\Core\ParamConverter\ParamConverterManagerInterface
    */
   protected $paramConverterManager;
 
   /**
-   * @param \Drupal\Core\ParamConverter\ParamConverterManager $param_converter_manager
+   * @param \Drupal\Core\ParamConverter\ParamConverterManagerInterface $param_converter_manager
    */
-  public function __construct(ParamConverterManager $param_converter_manager) {
+  public function __construct(ParamConverterManagerInterface $param_converter_manager) {
     $this->paramConverterManager = $param_converter_manager;
   }
 
@@ -35,46 +34,29 @@ public function __construct(ParamConverterManager $param_converter_manager) {
    * {@inheritdoc}
    */
   public function enhance(array $defaults, Request $request) {
-    // Store a backup of the raw $defaults values corresponding to
-    // variables in the route path pattern.
+    $defaults['_raw_variables'] = $this->copyRawVariables($defaults);
+    return $this->paramConverterManager->convert($defaults, $request);
+  }
+
+  /**
+   * Store a backup of the raw values that corresponding to the route pattern.
+   *
+   * @param array $defaults
+   *
+   * @return \Symfony\Component\HttpFoundation\ParameterBag
+   */
+  protected function copyRawVariables(array $defaults) {
     /** @var $route \Symfony\Component\Routing\Route */
     $route = $defaults[RouteObjectInterface::ROUTE_OBJECT];
     $variables = array_flip($route->compile()->getVariables());
-    // Foreach  will copy the values from the array it iterates. Even if they
+    // Foreach will copy the values from the array it iterates. Even if they
     // are references, use it to break them. This avoids any scenarios where raw
     // variables also get replaced with converted values.
     $raw_variables = array();
     foreach (array_intersect_key($defaults, $variables) as $key => $value) {
       $raw_variables[$key] = $value;
     }
-    $defaults['_raw_variables'] = new ParameterBag($raw_variables);
-
-    // Skip this enhancer if there are no parameter definitions.
-    if (!$parameters = $route->getOption('parameters')) {
-      return $defaults;
-    }
-
-    // Invoke the registered converter for each parameter.
-    foreach ($parameters as $name => $definition) {
-      if (!isset($defaults[$name])) {
-        // Do not try to convert anything that is already set to NULL.
-        continue;
-      }
-
-      if (!isset($definition['converter'])) {
-        // Continue if no converter has been specified.
-        continue;
-      }
-
-      // If a converter returns NULL it means that the parameter could not be
-      // converted in which case we throw a 404.
-      $defaults[$name] = $this->paramConverterManager->getConverter($definition['converter'])->convert($defaults[$name], $definition, $name, $defaults, $request);
-      if (!isset($defaults[$name])) {
-        throw new ParamNotConvertedException(sprintf('The "%s" parameter was not converted for the path "%s"', $name, $route->getPath()));
-      }
-    }
-
-    return $defaults;
+    return new ParameterBag($raw_variables);
   }
 
 }
diff --git a/core/tests/Drupal/Tests/Core/Access/AccessManagerTest.php b/core/tests/Drupal/Tests/Core/Access/AccessManagerTest.php
index b1e041f..0e830e2 100644
--- a/core/tests/Drupal/Tests/Core/Access/AccessManagerTest.php
+++ b/core/tests/Drupal/Tests/Core/Access/AccessManagerTest.php
@@ -63,11 +63,11 @@ class AccessManagerTest extends UnitTestCase {
   protected $urlGenerator;
 
   /**
-   * The route enhancer.
+   * The parameter converter.
    *
-   * @var \Symfony\Cmf\Component\Routing\Enhancer\RouteEnhancerInterface|\PHPUnit_Framework_MockObject_MockObject
+   * @var \Drupal\Core\ParamConverter\ParamConverterManagerInterface|\PHPUnit_Framework_MockObject_MockObject
    */
-  protected $routeEnhancer;
+  protected $paramConverter;
 
   /**
    * The mocked account.
@@ -119,11 +119,11 @@ protected function setUp() {
       ->method('generate')
       ->will($this->returnValueMap($map));
 
-    $this->routeEnhancer = $this->getMock('Symfony\Cmf\Component\Routing\Enhancer\RouteEnhancerInterface');
+    $this->paramConverter = $this->getMock('Drupal\Core\ParamConverter\ParamConverterManagerInterface');
 
     $this->account = $this->getMock('Drupal\Core\Session\AccountInterface');
 
-    $this->accessManager = new AccessManager($this->routeProvider, $this->urlGenerator, $this->routeEnhancer, $this->account);
+    $this->accessManager = new AccessManager($this->routeProvider, $this->urlGenerator, $this->paramConverter, $this->account);
     $this->accessManager->setContainer($this->container);
   }
 
@@ -152,7 +152,7 @@ public function testSetChecks() {
    */
   public function testSetChecksWithDynamicAccessChecker() {
     // Setup the access manager.
-    $this->accessManager = new AccessManager($this->routeProvider, $this->urlGenerator, $this->routeEnhancer, $this->account);
+    $this->accessManager = new AccessManager($this->routeProvider, $this->urlGenerator, $this->paramConverter, $this->account);
     $this->accessManager->setContainer($this->container);
 
     // Setup the dynamic access checker.
@@ -394,12 +394,12 @@ public function testCheckNamedRoute() {
     // Tests the access with routes without given request.
     $this->accessManager->setRequest(new Request());
 
-    $this->routeEnhancer->expects($this->at(0))
-      ->method('enhance')
+    $this->paramConverter->expects($this->at(0))
+      ->method('convert')
       ->will($this->returnValue(array()));
 
-    $this->routeEnhancer->expects($this->at(1))
-      ->method('enhance')
+    $this->paramConverter->expects($this->at(1))
+      ->method('convert')
       ->will($this->returnValue(array()));
 
     // Tests the access with routes with parameters without given request.
@@ -431,9 +431,9 @@ public function testCheckNamedRouteWithUpcastedValues() {
       ->method('generate')
       ->will($this->returnValueMap($map));
 
-    $this->routeEnhancer = $this->getMock('Symfony\Cmf\Component\Routing\Enhancer\RouteEnhancerInterface');
-    $this->routeEnhancer->expects($this->at(0))
-      ->method('enhance')
+    $this->paramConverter = $this->getMock('Drupal\Core\ParamConverter\ParamConverterManagerInterface');
+    $this->paramConverter->expects($this->at(0))
+      ->method('convert')
       ->will($this->returnValue(array('value' => 'upcasted_value')));
 
 
@@ -444,7 +444,7 @@ public function testCheckNamedRouteWithUpcastedValues() {
       ->with('/test-route-1/example')
       ->will($this->returnValue($subrequest));
 
-    $this->accessManager = new AccessManager($this->routeProvider, $this->urlGenerator, $this->routeEnhancer, $this->account);
+    $this->accessManager = new AccessManager($this->routeProvider, $this->urlGenerator, $this->paramConverter, $this->account);
     $this->accessManager->setContainer($this->container);
     $this->accessManager->setRequest(new Request());
 
@@ -491,9 +491,9 @@ public function testCheckNamedRouteWithDefaultValue() {
       ->with('test_route_1', array('value' => 'example'))
       ->will($this->returnValueMap($map));
 
-    $this->routeEnhancer = $this->getMock('Symfony\Cmf\Component\Routing\Enhancer\RouteEnhancerInterface');
-    $this->routeEnhancer->expects($this->at(0))
-      ->method('enhance')
+    $this->paramConverter = $this->getMock('Drupal\Core\ParamConverter\ParamConverterManagerInterface');
+    $this->paramConverter->expects($this->at(0))
+      ->method('convert')
       ->with(array('value' => 'example', RouteObjectInterface::ROUTE_OBJECT => $route))
       ->will($this->returnValue(array('value' => 'upcasted_value')));
 
@@ -504,7 +504,7 @@ public function testCheckNamedRouteWithDefaultValue() {
       ->with('/test-route-1/example')
       ->will($this->returnValue($subrequest));
 
-    $this->accessManager = new AccessManager($this->routeProvider, $this->urlGenerator, $this->routeEnhancer, $this->account);
+    $this->accessManager = new AccessManager($this->routeProvider, $this->urlGenerator, $this->paramConverter, $this->account);
     $this->accessManager->setContainer($this->container);
     $this->accessManager->setRequest(new Request());
 
@@ -578,7 +578,7 @@ public function testCheckException($return_value, $access_mode) {
       ->will($this->returnValue($return_value));
     $container->set('test_incorrect_value', $access_check);
 
-    $access_manager = new AccessManager($route_provider, $this->urlGenerator, $this->routeEnhancer);
+    $access_manager = new AccessManager($route_provider, $this->urlGenerator, $this->paramConverter);
     $access_manager->setContainer($container);
     $access_manager->addCheckService('test_incorrect_value');
 
@@ -633,7 +633,7 @@ protected static function convertAccessCheckInterfaceToString($constant) {
    * Adds a default access check service to the container and the access manager.
    */
   protected function setupAccessChecker() {
-    $this->accessManager = new AccessManager($this->routeProvider, $this->urlGenerator, $this->routeEnhancer, $this->account);
+    $this->accessManager = new AccessManager($this->routeProvider, $this->urlGenerator, $this->paramConverter, $this->account);
     $this->accessManager->setContainer($this->container);
     $access_check = new DefaultAccessCheck();
     $this->container->register('test_access_default', $access_check);
diff --git a/core/tests/Drupal/Tests/Core/Enhancer/ParamConversionEnhancerTest.php b/core/tests/Drupal/Tests/Core/Enhancer/ParamConversionEnhancerTest.php
index 42ced7d..f196232 100644
--- a/core/tests/Drupal/Tests/Core/Enhancer/ParamConversionEnhancerTest.php
+++ b/core/tests/Drupal/Tests/Core/Enhancer/ParamConversionEnhancerTest.php
@@ -27,7 +27,7 @@ class ParamConversionEnhancerTest extends UnitTestCase {
   protected $paramConversionEnhancer;
 
   /**
-   * @var \Drupal\Core\ParamConverter\ParamConverterManager|\PHPUnit_Framework_MockObject_MockObject
+   * @var \Drupal\Core\ParamConverter\ParamConverterManagerInterface|\PHPUnit_Framework_MockObject_MockObject
    */
   protected $paramConverterManager;
 
@@ -48,9 +48,7 @@ public static function getInfo() {
   protected function setUp() {
     parent::setUp();
 
-    $this->paramConverterManager = $this->getMockBuilder('Drupal\Core\ParamConverter\ParamConverterManager')
-      ->disableOriginalConstructor()
-      ->getMock();
+    $this->paramConverterManager = $this->getMock('Drupal\Core\ParamConverter\ParamConverterManagerInterface');
     $this->paramConversionEnhancer = new ParamConversionEnhancer($this->paramConverterManager);
   }
 
@@ -59,14 +57,6 @@ protected function setUp() {
    */
   public function testEnhance() {
     $route = new Route('/test/{id}/{literal}/{null}');
-    $parameters = array(
-      'id' => array(
-        'converter' => 'test_convert',
-      ),
-      'literal' => array(),
-      'null' => array(),
-    );
-    $route->setOption('parameters', $parameters);
 
     $raw_variables = array(
       'id' => 1,
@@ -81,15 +71,10 @@ public function testEnhance() {
     $expected['id'] = 'something_better!';
     $expected['_raw_variables'] = new ParameterBag($raw_variables);
 
-    $converter = $this->getMock('Drupal\Core\ParamConverter\ParamConverterInterface');
-    $converter->expects($this->any())
-      ->method('convert')
-      ->with(1, $this->isType('array'), 'id', $this->isType('array'), $this->isInstanceOf('Symfony\Component\HttpFoundation\Request'))
-      ->will($this->returnValue('something_better!'));
     $this->paramConverterManager->expects($this->any())
-      ->method('getConverter')
-      ->with('test_convert')
-      ->will($this->returnValue($converter));
+      ->method('convert')
+      ->with($this->isType('array'), $this->isInstanceOf('Symfony\Component\HttpFoundation\Request'))
+      ->will($this->returnValue($expected));
 
     $result = $this->paramConversionEnhancer->enhance($defaults, new Request());
 
@@ -97,53 +82,21 @@ public function testEnhance() {
   }
 
   /**
-   * @covers ::enhance()
+   * @covers ::copyRawVariables()
    */
-  public function testEnhanceNoConverting() {
-    $route = new Route('/test');
-    $defaults = array(
-      RouteObjectInterface::ROUTE_OBJECT => $route,
-    );
-
-    $expected = $defaults;
-    $expected['_raw_variables'] = new ParameterBag();
-
-    $result = $this->paramConversionEnhancer->enhance($defaults, new Request());
-    $this->assertEquals($expected, $result);
-  }
-
-  /**
-   * @covers ::enhance()
-   *
-   * @expectedException \Drupal\Core\ParamConverter\ParamNotConvertedException
-   */
-  public function testEnhanceMissingParam() {
+  public function testCopyRawVariables() {
     $route = new Route('/test/{id}');
-    $parameters = array(
-      'id' => array(
-        'converter' => 'test_convert',
-      ),
-    );
-    $route->setOption('parameters', $parameters);
-
-    $raw_variables = array(
-      'id' => 1,
-    );
     $defaults = array(
       RouteObjectInterface::ROUTE_OBJECT => $route,
-    ) + $raw_variables;
-
-    $converter = $this->getMock('Drupal\Core\ParamConverter\ParamConverterInterface');
-    $converter->expects($this->any())
-      ->method('convert')
-      ->with(1, $this->isType('array'), 'id', $this->isType('array'), $this->isInstanceOf('Symfony\Component\HttpFoundation\Request'))
-      ->will($this->returnValue(NULL));
+      'id' => '1',
+    );
     $this->paramConverterManager->expects($this->any())
-      ->method('getConverter')
-      ->with('test_convert')
-      ->will($this->returnValue($converter));
-
-    $this->paramConversionEnhancer->enhance($defaults, new Request());
+      ->method('convert')
+      ->with($this->isType('array'), $this->isInstanceOf('Symfony\Component\HttpFoundation\Request'))
+      ->will($this->returnArgument(0));
+    $expected = new ParameterBag(array('id' => 1));
+    $result = $this->paramConversionEnhancer->enhance($defaults, new Request());
+    $this->assertEquals($result['_raw_variables'], $expected);
   }
 
 }
diff --git a/core/tests/Drupal/Tests/Core/ParamConverter/ParamConverterManagerTest.php b/core/tests/Drupal/Tests/Core/ParamConverter/ParamConverterManagerTest.php
index 42ffeca..1d85dc1 100644
--- a/core/tests/Drupal/Tests/Core/ParamConverter/ParamConverterManagerTest.php
+++ b/core/tests/Drupal/Tests/Core/ParamConverter/ParamConverterManagerTest.php
@@ -9,6 +9,8 @@
 
 use Drupal\Core\ParamConverter\ParamConverterManager;
 use Drupal\Tests\UnitTestCase;
+use Symfony\Cmf\Component\Routing\RouteObjectInterface;
+use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\Routing\Route;
 use Symfony\Component\Routing\RouteCollection;
 
@@ -216,4 +218,92 @@ public function providerTestSetRouteParameterConverters() {
     );
   }
 
+  /**
+   * @covers ::convert()
+   */
+  public function testConvert() {
+    $route = new Route('/test/{id}/{literal}/{null}');
+    $parameters = array(
+      'id' => array(
+        'converter' => 'test_convert',
+      ),
+      'literal' => array(),
+      'null' => array(),
+    );
+    $route->setOption('parameters', $parameters);
+
+    $defaults = array(
+      RouteObjectInterface::ROUTE_OBJECT => $route,
+      'id' => 1,
+      'literal' => 'this is a literal',
+      'null' => NULL,
+    );
+
+    $expected = $defaults;
+    $expected['id'] = 'something_better!';
+
+    $converter = $this->getMock('Drupal\Core\ParamConverter\ParamConverterInterface');
+    $converter->expects($this->any())
+      ->method('convert')
+      ->with(1, $this->isType('array'), 'id', $this->isType('array'), $this->isInstanceOf('Symfony\Component\HttpFoundation\Request'))
+      ->will($this->returnValue('something_better!'));
+    $this->manager->addConverter('test_convert');
+    $this->container->expects($this->once())
+      ->method('get')
+      ->with('test_convert')
+      ->will($this->returnValue($converter));
+
+    $result = $this->manager->convert($defaults, new Request());
+
+    $this->assertEquals($expected, $result);
+  }
+
+  /**
+   * @covers ::convert()
+   */
+  public function testConvertNoConverting() {
+    $route = new Route('/test');
+    $defaults = array(
+      RouteObjectInterface::ROUTE_OBJECT => $route,
+    );
+
+    $expected = $defaults;
+
+    $result = $this->manager->convert($defaults, new Request());
+    $this->assertEquals($expected, $result);
+  }
+
+  /**
+   * @covers ::convert()
+   *
+   * @expectedException \Drupal\Core\ParamConverter\ParamNotConvertedException
+   */
+  public function testConvertMissingParam() {
+    $route = new Route('/test/{id}');
+    $parameters = array(
+      'id' => array(
+        'converter' => 'test_convert',
+      ),
+    );
+    $route->setOption('parameters', $parameters);
+
+    $defaults = array(
+      RouteObjectInterface::ROUTE_OBJECT => $route,
+      'id' => 1,
+    );
+
+    $converter = $this->getMock('Drupal\Core\ParamConverter\ParamConverterInterface');
+    $converter->expects($this->any())
+      ->method('convert')
+      ->with(1, $this->isType('array'), 'id', $this->isType('array'), $this->isInstanceOf('Symfony\Component\HttpFoundation\Request'))
+      ->will($this->returnValue(NULL));
+    $this->manager->addConverter('test_convert');
+    $this->container->expects($this->once())
+      ->method('get')
+      ->with('test_convert')
+      ->will($this->returnValue($converter));
+
+    $this->manager->convert($defaults, new Request());
+  }
+
 }