'Make sure we can manually set the From header (#9214)'

def test_from_header(self):

    email = EmailMessage(u'Subject', u'Content', u'bounce@example.com', [u'to@example.com'], headers={u'From': u'from@example.com'})
    message = email.message()
    self.assertEqual(message[u'From'], u'from@example.com')
