public function testConstructor()
{
$stream = new Stream();
$headers = ['Content-Type' => ['text/html;charset=utf-8']];
$protocol = '1.0';
$message = new Message($stream, $headers, $protocol);
$this->assertSame($stream, $message->getBody());
$this->assertSame($headers, $message->getHeaders());
$this->assertSame($protocol, $message->getProtocolVersion());
}