def test_copyUIDsFails(self):
        """
        L{IMAP4Client.copy} returns a L{Deferred} that fails with an
        L{IMAP4Exception} when the messages specified by the given
        UIDs could not be copied to the mailbox.
        """
        d = self.client.copy("2:3", "MEETING", uid=True)

        self.assertEqual(
            self.transport.value(),
            b"0001 UID COPY 2:3 MEETING\r\n",
        )

        self.client.lineReceived(b"0001 BAD COPY failed")
        self.assertIsInstance(self.failureResultOf(d).value,
                              imap4.IMAP4Exception)

        L{IMAP4Client.copy} returns a L{Deferred} that fails with an
        L{IMAP4Exception} when the messages specified by the given
        UIDs could not be copied to the mailbox.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/mail/test/test_imap.py