public function testPostParametersTransferred()
 {
     $this->getSlimInstance()->post('/post', function ($req, $res) {
         return $res->write((string) $req->getBody());
     });
     $client = new WebTestClient($this->getSlimInstance());
     $data = ['test' => 'data'];
     $body = $client->post('/post', $data);
     self::assertEquals(json_encode($data), $body);
 }