service: Add result parser to make the @return more useful.

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>
service_unittest: fix some unittest to adapt to result parser.

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>
Some fix according to comments.

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>