In the code under test, we sometimes want to preserve system functions, especially memory functions such as memcpy and memSET, which may affect coverage. The SmartRocket Unit is able to automatically capture the memory change constraints of such functions to generate the correct test cases, which are not properly recognized by tools that randomly generate or data dictionary generate test cases. Neither of the tools based on the first two generation strategies can properly override the return 0 branch, whereas the SmartRocket Unit provides a switch for whether the system function piles or not. When we turn on the system function no-pile switch, the SmartRocket Unit is able to correctly generate 2 use cases to achieve 100% coverage.