Code Coverage Analysis And Path Selection Technology Research And Application

In order to reduce the cost of test and avoid the testers imposing their own errors on software, people pay more and more attention on automatic test. Unit test is the minimum level of testing activities in the software development process, and most software errors are found in it. The path selection can provide the basis for the test case generation in automatic unit test, and code coverage can be used to measure the adequacy of automatic unit test.Focusing on the code coverage analysis techniques and the path selection techniques in automatic unit test, this thesis does following works.(1) This thesis does some research on the coverage statistical method of multi-coverage, and proposes the instrument message path, short for M-path, to compute the path num and decide the effectiveness of the test case in path coverage.(2) To improve the path selection in automating unit testing system, short for UATS, this thesis puts forward zero-one strategy on the loop path segments selection. For this zero-one strategy, this thesis uses the widening operator and narrowing operator to improve the interval arithmetic accuracy of the node on the loop path fragment. Meanwhile, for the combination of the condition on some decision nodes have been selected, this thesis has joined the calculation of the combination of the condition on the decision node into the interval arithmetic, increasing the accuracy of the infeasible path detection.(3) This thesis also proposes full-path re-selection and half-path selection strategies to increase the probability of selecting the feasible path. Full-path re-selection strategy used branch replacement and the combination of the condition replacement to re-selection a full-path. Half-path is a path fragment that is from the entry of control flow graph node to the target element. The selecting of half-path effectively increased the probability of selecting a feasible path by eliminating the infeasible caused by the path segments after the target node.The author carried out some experiments on multi-coverage computing system to verify the multi-coverage statistics function based on the realization of code coverage analysis technologies. At the same time, the thesis realized the path selection method on unit automatic test system short for UATS, and completed the comparison experiment of these three kinds of path selection strategies based on the UATS. The improvement of the coverage verified that it’s a successful modification for the path selection method in UATS by using full-path re-selection and half-path selection strategies.