In order to obtain accurate data which evaluating
software quality needed, we should carry out the necessary
and sufficient tests should be carried out. We use fault tree
analysis method, equivalence class partition method and
boundary value analysis method to design test cases. Fault
tree analysis method was first used for system reliability
analysis and design. In the designing test cases for failure
mode decision software, we adopted this method, which
greatly improved the scientificity of test case design and
reasonableness of test case distribution.