private function validate()
    {
        if (!$this->testServer($this->ssh, sprintf('-d "%s"', $this->directory))) {
            throw new SshValidateException('Directory does not exists');
        }

        if (!$this->testServer($this->ssh, sprintf('-x "%s"', $this->executable), $this->directory)) {
            throw new SshValidateException('Executable does not exists');
        }

        return true;
    }