08white2数据流覆盖.pptVIP

More Dataflow Terms and Definitions A path (either partial or complete) is simple if all edges within the path are distinct (i.e., different). A path is loop-free if all nodes within the path are distinct (i.e., different). Simple and Loop-Free Paths path Simple? Loop-free? 1,3,4,2 1,2,3,2 1,2,3,1,2 1,2,3,2,4 Simple and Loop-Free Paths (cont’d) Which is stronger, simple or loop-free? More Dataflow Terms and Definitions A path n1,n2,...,nj,nk is a du-path with respect to a variable v if v is defined at node n1 and either: there is a c-use of v at node nk and n1,n2,...,nj,nk is a def-clear simple path, or there is a p-use of v at edge nj,nk and n1,n2,...nj is a def-clear loop-free path. More Dataflow Terms and Definitions A path n1,n2,...,nj,nk is a du-path with respect to a variable v if v is defined at node n1 and either: there is a c-use of v at node nk and n1,n2,...,nj,nk is a def-clear simple path, or there is a p-use of v at edge nj,nk and n1,n2,...nj is a def-clear loop-free path. NOTE! Identifying du-paths du-pair path(s) du-path? X: (5,7) 5,6,7 ? 5,6,3,4,6,7 5,6,3,4,6,(3,4,6)*,7 X: (5,3,4) 5,6,3,4 5,6,3,4,(6,3,4)* X: (5,3,5) 5,6,3,5 5,6,3,4,6,3,5 ? 5,6,3,4,6,(3,4,6)*,3,5 ? ? infeasible Another Dataflow Test Coverage Criterion All-DU-Paths: for every program variable v, every du-path from every definition of v to every c-use and every p-use of v must be covered. Exercise Identify all c-uses and p-uses for variable Y in Example 2. For each c-use or p-use, identify (using the “ * ” notation) all def-clear paths. Identify whether or not each def-clear path is feasible, and whether or not it is a du-path. Summary of White-Box Coverage Relationships Path All du-paths All-Uses All-Defs Compound Condition Branch / Condition Basis Paths Loop Condition Statement Branch * * - nominal cases * White-Box Testing Techniques II Prepared by Stephen M. Thebaut, Ph.D. University of Florida Software Testing and Verification Lecture 8 Def-Clear Paths Subsum