'Test send_mail without the html_message
regression test for adding html_message parameter to send_mail()'

def test_plaintext_send_mail(self):

    send_mail('Subject', 'Content', 'sender@example.com', ['nobody@example.com'])
    message = self.get_the_message()
    self.assertEqual(message.get('subject'), 'Subject')
    self.assertEqual(message.get_all('to'), ['nobody@example.com'])
    self.assertFalse(message.is_multipart())
    self.assertEqual(message.get_payload(), 'Content')
    self.assertEqual(message.get_content_type(), 'text/plain')
