Merge branch '6.4' into 7.1

* 6.4:
  Add info about troubleshooting assets loading with Panther. - Can happen with any requested uri that look like a non `.php` file - Case can happen with AssetMapper.

Author: javiereguiluz

frontend/asset_mapper.rst

@@ -73,6 +73,8 @@ If you look at the HTML in your page, the URL will be something
 like: ``/assets/images/duck-3c16d9220694c0e56d8648f25e6035e9.png``. If you change
 the file, the version part of the URL will also change automatically.
 
+.. _asset-mapper-compile-assets:
+
 Serving Assets in dev vs prod
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

testing/end_to_end.rst

@@ -799,6 +799,54 @@ variable to ``false`` in your style file:
 
     $enable-smooth-scroll: false;
 
+Assets not Loading when Using the PHP Built-In Server
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Sometimes, your assets might not load during tests. This happens because Panther
+uses the `PHP built-in server`_ to serve your app. If asset files (or any requested
+URI that's not a ``.php`` file) aren't in your public directory, the built-in
+server will return a 404 error. This often happens when letting the :doc:`AssetMapper component </frontend/asset_mapper>`
+handle your application assets in the ``dev`` environment.
+
+One solution when using AssetMapper is to ref:`compile assets <asset-mapper-compile-assets>`
+before running your tests. This will also speed up your tests, as Symfony won't
+need to handle the assets, allowing the PHP built-in server to serve them directly.
+
+Another option is to create a file called ``tests/router.php`` and add the following to it::
+
+    // tests/router.php
+    if (is_file($_SERVER['DOCUMENT_ROOT'].\DIRECTORY_SEPARATOR.$_SERVER['SCRIPT_NAME'])) {
+        return false;
+    }
+
+    $script = 'index.php';
+
+    $_SERVER = array_merge($_SERVER, $_ENV);
+    $_SERVER['SCRIPT_FILENAME'] = $_SERVER['DOCUMENT_ROOT'].\DIRECTORY_SEPARATOR.$script;
+
+    $_SERVER['SCRIPT_NAME'] = \DIRECTORY_SEPARATOR.$script;
+    $_SERVER['PHP_SELF'] = \DIRECTORY_SEPARATOR.$script;
+
+    require $script;
+
+Then declare it as a router for Panther server in ``phpunit.xml.dist`` using the
+``PANTHER_WEB_SERVER_ROUTER`` environment variable:
+
+.. code-block:: xml
+
+    <!-- phpunit.xml.dist -->
+    <phpunit>
+        <!-- ... -->
+        <php>
+            <!-- ... -->
+            <server name="PANTHER_WEB_SERVER_ROUTER" value="./tests/router.php"/>
+        </php>
+    </phpunit>
+
+.. seealso::
+
+    See the `Functional Testing tutorial`_ on SymfonyCasts.
+
 Additional Documentation
 ------------------------
 
@@ -825,3 +873,5 @@ documentation:
 .. _`Gitlab CI`: https://docs.gitlab.com/ee/ci/
 .. _`AppVeyor`: https://www.appveyor.com/
 .. _`LiipFunctionalTestBundle`: https://github.com/liip/LiipFunctionalTestBundle
+.. _`PHP built-in server`: https://www.php.net/manual/en/features.commandline.webserver.php
+.. _`Functional Testing tutorial`: https://symfonycasts.com/screencast/last-stack/testing