VNF sizing is one of the big issues for users, integrators and also venders/providers of VNF. In legacy system, network functions are integrated in the systems with carefully sizing by estimated performance metrics, but in NFV, performance and metrics of VNF are depends on flavors. To decide which flavor is suitable for requirements, we have to know the basic data of each metrics with variable flavors. But there are many parameters, so automatic testing is necessary. We had developed the test automation system of VNF that can automatically conducting the sequence of tests with variable parameters such as number of core, memory size, interface speed, etc. We already created the test cases that evaluate BGP interoperability of virtual router and performance test of Cisco, Juniper, Brocade, and so on. We think the activity is similar to Yardstick, so we would like to collaborate with them. In this talk, we summarize our activities and development result, and introducing our latest plan to collaborate with OPNFV.