'Be sure that caller CANNOT change the form charset for
encoding type.'

def test_overrideRequired(self):

    m = message.Message.fromPostArgs(self.postargs)
    tag_attrs = dict(self.form_tag_attrs)
    tag_attrs['accept-charset'] = 'UCS4'
    tag_attrs['enctype'] = 'invalid/x-broken'
    html = m.toFormMarkup(self.action_url, tag_attrs, self.submit_text)
    self._checkForm(html, m, self.action_url, tag_attrs, self.submit_text)
