'Perform the request and compare with non_existent
:see _create_tests: For parameter description
:return: The HTTP response id if the mutated_url is a web user
directory, None otherwise.'

def _check_user_dir(self, mutated_url, user, user_desc, user_tag, non_existent):

    resp = self.http_get_and_parse(mutated_url)
    path = mutated_url.get_path()
    response_body = resp.get_body().replace(path, '')
    if fuzzy_not_equal(response_body, non_existent, 0.7):
        user_infos = kb.kb.get('user_dir', 'users')
        known_users = [u.get('user', None) for u in user_infos]
        if (user in known_users):
            return
        desc = 'An    operating    system    user    directory    was    found    at:    "%s"'
        desc %= resp.get_url()
        i = Info('Web    user    home    directory', desc, resp.id, self.get_name())
        i.set_url(resp.get_url())
        i['user'] = user
        i['user_desc'] = user_desc
        i['user_tag'] = user_tag
        self.kb_append_uniq(self, 'users', i)
        self._analyze_finding(i)
