def setUp(self):
        super(SimpleInstanceTest, self).setUp()
        db_info = DBInstance(
            InstanceTasks.BUILDING, name="TestInstance")
        self.instance = SimpleInstance(
            None, db_info, InstanceServiceStatus(
                ServiceStatuses.BUILDING), ds_version=Mock(), ds=Mock())
        db_info.addresses = {"private": [{"addr": "123.123.123.123"}],
                             "internal": [{"addr": "10.123.123.123"}],
                             "public": [{"addr": "15.123.123.123"}]}
        self.orig_conf = CONF.network_label_regex
        self.orig_ip_regex = CONF.ip_regex
        self.orig_black_list_regex = CONF.black_list_regex
def dfs(self, num, target, pos, cur_str, cur_val, mul, ret):
        if pos >= len(num):
            if cur_val == target:
                ret.append(cur_str)
        else:
            for i in xrange(pos, len(num)):
                if i != pos and num[pos] == "0":
                    continue
                nxt_val = int(num[pos:i+1])

                if not cur_str:
                    self.dfs(num, target, i+1, "%d"%nxt_val, nxt_val, nxt_val, ret)
                else:
                    self.dfs(num, target, i+1, cur_str+"+%d"%nxt_val, cur_val+nxt_val, nxt_val, ret)
                    self.dfs(num, target, i+1, cur_str+"-%d"%nxt_val, cur_val-nxt_val, -nxt_val, ret)
                    self.dfs(num, target, i+1, cur_str+"*%d"%nxt_val, cur_val-mul+mul*nxt_val, mul*nxt_val, ret)