In order to analyze and test the component-based web application and decide when to stop the testing process, the concept of coverage criteria and test requirement reduction approach are proposed. First, four adequacy criteria are defined and subsumption relationships among them are proved. Then, a translation algorithm is presented to transfer the test model into a web application decision-to-decision graph（WADDGraph）which is used to reduce testing requirements. Finally, different sets of test requirements can be generated from WADDGraph by analyzing subsumption and equivalence relationships among edges based on different coverage criteria, and testers can select different test requirements according to different testing environments. The case study indicates that coverage criteria follow linear subsumption relationships in real web applications. Test requirements can be reduced more than 55% on average based on different coverage criteria and the size of test requirements increases with the increase in the complexity of the coverage criteria.
A t-covering array of size N, degree k, order v and strength t is an N x k array with entries from a set of v symbols such that any N x t subarray contains a t-tuple of v symbols at least once as a row. This paper presents a new algebraic recursive method for constructing covering arrays based on difference matrices. The method can extend parameter factors on the existing covering arrays and cover all the combinations of any t parameter factors （t≥2）. The method, which recursively generates high strength covering arrays, is practical. Meanwhile, the theoretical derivation and realization of the proposed algebraic recursive algorithm are given.
Based on the different roles played by base flow and alternative flow in the process to achieve user＇s goals, we have found that loop structure is frequently used to implement alternative flow and/or to connect different use cases. This paper presents an approach to identify base flows and alternative flows of different use cases by traversing control flow graph in which back edges are eliminated. The effectiveness of the approach is verified by identification of the use case structure of an ATM system. The workload of human intervention of the approach is relatively slight, and the manner of human intervention closely follows the usual process of software comprehension.
A simplified integer overflow detection method based on path relaxation is described for avoiding buffer overflow triggered by integer overflow. When the integer overflow refers to the size of the buffer allocated dynamically, this kind of integer overflow is most likely to trigger buffer overflow. Based on this discovery, through lightly static program analysis, the solution traces the key variables referring to the size of a buffer allocated dynamically and it maintains the upper bound and lower bound of these variables. After the constraint information of these traced variables is inserted into the original program, this method tests the program with test cases through path relaxation, which means that it not only reports the errors revealed by the current runtime value of traced variables contained in the test case, but it also examines the errors possibly occurring under the same execution path with all the possible values of the traced variables. The effectiveness of this method is demonstrated in a case study. Compared with the traditional buffer overflow detection methods, this method reduces the burden of detection and improves efficiency.
Website navigability is acquiring a growing importance in website design and redesign,quality evaluation,and improvement.Existing navigability measures mainly depend on site link structure,so that they only consider the impact of site link structure for navigability and ignore the impact of Web page content.A continuous Markov chain model which depicts the user＇s surfing behavior can balance these two factors in the evaluation of website navigability,and it needs to estimate the page transition probabilities and user stay time according to user access log.In this way,we can obtain more reliable results for website navigability measure than the existed methods.Experiments show that our method is effective.
