public function testCreateRelationViaMultipartForm()
    {
        print "\n" . "Test: create relation X has narrower Y via multipart-form ";
        $this->AssertEquals(201, self::$responseX->getStatus(), "\n Cannot perform the test because something is wrong with creating a test concept X: " . self::$responseX->getHeader('X-Error-Msg'));
        $this->AssertEquals(201, self::$responseY->getStatus(), "\n Cannot perform the test because something is wrong with creating a test concept Y: " . self::$responseY->getHeader('X-Error-Msg'));
        $boundary = '36374246216810994721943965972';
        $body = '--36374246216810994721943965972
Content-Disposition: form-data; name="concept"
' . self::$aboutX . "\n" . '--36374246216810994721943965972' . "\n" . 'Content-Disposition: form-data; name="type"
http://www.w3.org/2004/02/skos/core#narrower
--36374246216810994721943965972
Content-Disposition: form-data; name="related"
' . self::$aboutY . "\n" . '--36374246216810994721943965972
Content-Disposition: form-data; name="tenant"
mi
--36374246216810994721943965972
Content-Disposition: form-data; name="key"
apikey
--36374246216810994721943965972--';
        $response = RequestResponse::CreateRelationMultipartFormRequest(self::$client, $body, $boundary);
        $this->AssertEquals(200, $response->getStatus(), $response->getHeader('X-Error-Msg'));
        // todo: add assertions
    }