def test_fetchParserHeaderMissingParentheses(self):
        """
        Parsing a C{BODY} whose C{HEADER.FIELDS} list does not begin
        with an open parenthesis (C{(}) or end with a close
        parenthesis (C{)}) raises an L{Exception}.
        """
        p = imap4._FetchParser()
        self.assertRaises(Exception,
                          p.parseString, b"BODY[HEADER.FIELDS Missing)]")
        p = imap4._FetchParser()
        self.assertRaises(Exception,
                          p.parseString, b'BODY[HEADER.FIELDS (Missing]')

        Parsing a C{BODY} whose C{HEADER.FIELDS} list does not begin
        with an open parenthesis (C{(}) or end with a close
        parenthesis (C{)}) raises an L{Exception}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/mail/test/test_imap.py