'Email line length is limited to 998 chars by the RFC:
https://tools.ietf.org/html/rfc5322#section-2.1.1
Message body containing longer lines are converted to Quoted-Printable
to avoid having to insert newlines, which could be hairy to do properly.'

def test_send_long_lines(self):

    email = EmailMessage('Subject', ('\xd0\x92    \xd1\x8e\xd0\xb6\xd0\xbd\xd1\x8b\xd1\x85    \xd0\xbc\xd0\xbe\xd1\x80\xd1\x8f\xd1\x85    ' * 60), 'from@example.com', ['to@example.com'])
    email.send()
    message = self.get_the_message()
    self.assertMessageHasHeaders(message, {('MIME-Version', '1.0'), ('Content-Type', 'text/plain;    charset="utf-8"'), ('Content-Transfer-Encoding', 'quoted-printable')})
