def METHOD_NAME(self):
    source = ("Subject: Maintenant je vous présente mon "
             "collègue\n\n").encode('utf-8')
    expected = ('Subject: Maintenant je vous =?unknown-8bit?q?'
                'pr=C3=A9sente_mon_coll=C3=A8gue?=\n\n').encode('ascii')
    msg = message_from_bytes(source)
    s = io.BytesIO()
    g = BytesGenerator(s, policy=self.policy.clone(cte_type='7bit'))
    g.flatten(msg)
    self.assertEqual(s.getvalue(), expected)