Fix missing dependence and data typing

composer.json

@@ -25,7 +25,8 @@
         "guzzlehttp/guzzle": "^6.3",
         "slim/slim": "^3.12",
         "friendsofphp/php-cs-fixer": "^2.16",
-        "sensiolabs/security-checker": "^6.0"
+        "sensiolabs/security-checker": "^6.0",
+        "symfony/http-foundation": "^5.0"
     },
     "require-dev": {
         "internations/testing-component": "1.3.0",

src/Server.php

@@ -43,7 +43,7 @@ public function start(callable $callback = null, array $env = [])
         $this->pollWait();
     }
 
-    public function stop($timeout = 10, int $signal = null)
+    public function stop($timeout = 10, $signal = null)
     {
         return parent::stop($timeout, $signal);
     }

src/Util.php

@@ -2,6 +2,8 @@
 
 namespace InterNations\Component\HttpMock;
 
+use function GuzzleHttp\Psr7\parse_response;
+use function GuzzleHttp\Psr7\str;
 use UnexpectedValueException;
 
 final class Util
@@ -26,12 +28,11 @@ public static function silentDeserialize($string)
 
     public static function responseDeserialize($string)
     {
-        return \GuzzleHttp\Psr7\parse_response($string);
+        return parse_response($string);
     }
 
     public static function serializePsrMessage($message)
     {
-        $fixedHeaders = [];
         $headers = $message->getHeaders();
         foreach ($headers as $key => $list) {
             foreach ($list as $value) {
@@ -46,6 +47,6 @@ public static function serializePsrMessage($message)
             }
         }
 
-        return \GuzzleHttp\Psr7\str($message);
+        return str($message);
     }
 }