$this->headers must be an instance of Headers

[michalbundyra]

If subject is NULL (mail have no subject) I got this exception

$this->headers must be an instance of Headers

Need to handle NULL subject without error/exception.

---

Originally posted by @r0073rr0r at zendframework/zend-mail#167

[michalbundyra]

Please provide code and/or unit test to reproduce the error. I tried the following test and it works:

    public function testAllowMessageWithEmptySubject()
    {
        $message = new Message();
        $message->addTo('[email protected]')
                ->setSender('[email protected]', 'Ralph Schindler')
                ->setBody('This is only a test.');

        $this->transport->send($message);
    }

---

Originally posted by @samsonasik at zendframework/zend-mail#167 (comment)

[samsonasik]

I am closing it since there is no code/unit test to reproduce the issue.