Research On Software Testing Technology Based On Defect Pattern

With the development of information technology, the scale of software extends continuously, and how to guarantee and raise software quality becomes the main point in the software field. The frequent software crises enhance the position of software testing unprecedentedly.Software testing based on defect pattern is a new kind of source code static analysis technology, and it is mainly used in automatic and semi-automatic defect testing and precaution. For their high performance and easy use, such tools are widely applied in highly dependable software fields. The defect pattern is defined as often occurrences of program errors or defects, and defect patterns are usually summarized by experienced program designers and testers. As the beneficial supplement of traditional software testing, the main advantages of this technology are:(1) unlike the uncertainty of white box and black box testing, it is very pertinent to program defects; (2) it can detect defects that happen in lower probability such as memory leak and null pointer dereference.Supported by the National High-tech Research and Development Program ("863" Program) "Software fault models and the fault oriented software testing system" and "The product line supporting software dependability analysis and evaluation", this paper focuses on several static analysis technologies involved in defect pattern checking. It mainly discusses the classification of defect patterns and the general detecting model, variable range analysis methods and path sensitive analysis method based on data flow analysis. The main contributions are as follows:(1) Based on the graveness which defects may result in, software defects are divided into four classes:fault patterns, security vulnerability patterns, suspicious code patterns and program rule patterns. A general defect pattern checking model is proposed, in which accuracy enhancement and automatic testing are the kernel parts. In this model, defect pattern database and defect detecting are separate, and defect patterns are described unifiedly, so they can be customized and configured flexibly. Defect pattern state machines are independent, so the model can check many defect patterns concurrently.(2) Based on abstract interpretation theory, this paper extends classical interval abstraction, and extended intervals are used to describe variable range. The concept of numeric interval-set is proposed for the first time, and fundamental operations on interval-sets are defined. Boolean interval algebra and Reference interval algebra are also proposed. For range analysis in conditional expressions, split operation and logic operation are defined. Furthermore, to improve computing efficiency, the possible-value-set and necessary-value-set are put forward to compute variable range in conditional expressions.Then, a general algorithm for intra-procedural and inter-procedural range analysis is given. The algorithm can detect a great number of paradoxical statement nodes and infeasible paths in program, and defect detecting tool based on it can improve testing efficiency.(3) A new path sensitive analysis method is given, in which the property state condition is described by extended interval. It emerges property state conditions of the same property state at join points in CFG to depress computing complexity, and it runs in polynomial time and space. Experiments show that this method has lower false positive rate.Based on the above contributions, a practical software defect detecting tool-DTS (Defect Testing System) is introduced, and its interface design and system functions are given. Compared with several popular defect testing tools, DTS has satisfied testing results.