diff --git a/libs/DauxHelper.php b/libs/DauxHelper.php
index 2b97f5d..845121c 100644
--- a/libs/DauxHelper.php
+++ b/libs/DauxHelper.php
@@ -488,6 +488,11 @@ class DauxHelper
      * @return false|null|string
      */
     public static function findLocation($path, $basedir, $var, $type) {
+        // VFS, used only in tests
+        if (substr($path, 0, 6) == "vfs://") {
+            return $path;
+        }
+
         // When running through `daux --serve` we set an environment variable to know where we started from
         $env = getenv($var);
         if ($env && DauxHelper::is($env, $type)) {
diff --git a/tests/Server/ServerTest.php b/tests/Server/ServerTest.php
new file mode 100644
index 0000000..60a78c2
--- /dev/null
+++ b/tests/Server/ServerTest.php
@@ -0,0 +1,39 @@
+<?php namespace Todaymade\Daux\Server;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Console\Output\NullOutput;
+use Symfony\Component\HttpFoundation\Request;
+use Todaymade\Daux\Format\HTML\RawPage;
+use Todaymade\Daux\Config;
+use Todaymade\Daux\Daux;
+use Todaymade\Daux\Server\Server;
+use org\bovigo\vfs\vfsStream;
+
+class ServerTest extends TestCase
+{
+    function testCreateResponse() {
+
+        $structure = [
+            'index.md' => 'first page',
+            'Page.md' => 'another page',
+            'somefile.css' => 'body {}',
+            '22.png' => ''
+        ];
+        $root = vfsStream::setup('root', null, $structure);
+
+        $daux = new Daux(Daux::LIVE_MODE, new NullOutput());
+        $daux->getParams()->setDocumentationDirectory($root->url());
+
+        $daux->initializeConfiguration();
+        $daux->getParams()['index_key'] = 'index';
+        $daux->generateTree();
+
+        $page = new RawPage($daux->tree['somefile.css']->getPath());
+
+        $server = new Server($daux);
+        $response = $server->createResponse($page)->prepare(Request::createFromGlobals());
+
+        $this->assertEquals("text/css", $response->headers->get('Content-Type'));
+    }
+}
+