public function responseIsSuccessfully()
    {
        Assertions::assertEquals(200, $this->response->getStatusCode(), sprintf(
            'Response with error "%s".',
            $this->response->getBody()
        ));

        Assertions::assertNull($this->response->getRpcErrorCode(), sprintf(
            'Response with error "%s".',
            $this->response->getBody()
        ));
    }