I. Background
Software test planning is a crucial topic for the hardware/software development companies. It is not only important but also expensive once we want to go through a system (combine with software and hardware) development process. Many sequences of possible inputs must be checked to verify the behavior a system. Investigation says that the software test planning and testing requires at least 50% cost of the total cost, but it may cost higher once the hardware and safety-critical services are included [1]. The National Institute of Standards and Technology (NIST) estimated that the annual cost of inadequate testing in US as much as $59 billion [2]. This estimation focuses the significance of effective methods for software test planning.