Respective processing hierarchies of a control program of an electronic control system and a testing program of a testing apparatus are each configured in the same manner; requesting data for each of processing hierarchies of the control program to be executed by the electronic control system is created without making any change in a required communication specification between a transmission direction and a reception direction; requesting data for each of processing hierarchies of the testing program to be executed by the testing apparatus is created while changing a transmission direction of communication requesting data to a reception direction thereof and changing the reception direction to the transmission direction.