Provide test functionality in traits

Fix #202.

separate http client from trait

Make property and methods private

Add traits to docs

Author: ddeboer

doc/includes/symfony-process.rst

@@ -0,0 +1,6 @@
+Requires Symfony’s Process component, so make sure to include that in your
+project:
+
+.. code-block:: bash
+
+    $ composer require symfony/process

doc/proxy-clients.rst

@@ -66,6 +66,8 @@ Then pass that adapter to the caching proxy client::
     $proxyClient = new Varnish($servers, '/baseUrl', $adapter);
     // Varnish as example, but also possible for NGINX and Symfony
 
+.. _varnish client:
+
 Varnish Client
 ~~~~~~~~~~~~~~
 

doc/symfony-cache-configuration.rst

@@ -179,4 +179,34 @@ the ``session_name_prefix`` option) in the requests to the backend. If you need
 a different behavior, overwrite ``UserContextSubscriber::cleanupHashLookupRequest``
 with your own logic.
 
+.. _symfony-cache x-debugging:
+
+Debugging
+~~~~~~~~~
+
+For the ``assertHit`` and ``assertMiss`` assertions to work, you need to add
+debug information in your AppCache. Create the cache kernel with the option
+``'debug' => true`` and add the following to your ``AppCache``::
+
+    public function handle(Request $request, $type = HttpKernelInterface::MASTER_REQUEST, $catch = true)
+    {
+        $response = parent::handle($request, $type, $catch);
+
+        if ($response->headers->has('X-Symfony-Cache')) {
+            if (false !== strpos($response->headers->get('X-Symfony-Cache'), 'miss')) {
+                $state = 'MISS';
+            } elseif (false !== strpos($response->headers->get('X-Symfony-Cache'), 'fresh')) {
+                $state = 'HIT';
+            } else {
+                $state = 'UNDETERMINED';
+            }
+            $response->headers->set('X-Cache', $state);
+        }
+
+        return $response;
+    }
+
+The ``UNDETERMINED`` state should never happen. If it does, it means that your
+HttpCache is not correctly set into debug mode.
+
 .. _HttpCache: http://symfony.com/doc/current/book/http_cache.html#symfony-reverse-proxy