tailieunhanh - Lecture Software testing and analysis: Chapter 5 - Mauro Pezzè, Michal Young

This chapter presents some basic concepts in models of software and some families of models that are used in a wide variety of testing and analysis techniques. The fundamental concepts and trade-offs in the design of models is necessary for a full understanding of those test and analysis techniques, and is a foundation for devising new techniques and models to solve domain-specific problems. | Finite Models (c) 2007 Mauro Pezzè & Michal Young Ch 5, slide 1 Learning objectives • Understand goals and implications of finite state abstraction • Learn how to model program control flow with graphs • Learn how to model the software system structure with call graphs • Learn how to model finite state behavior with finite state machines (c) 2007 Mauro Pezzè & Michal Young Ch 5, slide 2 Properties of Models • Compact: representable and manipulable in a reasonably compact form – What is reasonably compact depends largely on how the model will be used • Predictive: must represent some salient characteristics of the modeled artifact well enough to distinguish between good and bad outcomes of analysis – no single model represents all characteristics well enough to be useful for all kinds of analysis • Semantically meaningful: it is usually necessary to interpret analysis results in a way that permits diagnosis of the causes of failure • Sufficiently general: models intended for analysis of some important characteristic must be general enough for practical use in the intended domain of application (c) 2007 Mauro Pezzè & Michal Young Ch 5, slide 3 Graph Representations: directed graphs • Directed graph: – N (set of nodes) – E (relation on the set of nodes ) edges Nodes: {a, b, c} Edges: {(a,b), (a, c), (c, a)} a b b (c) 2007 Mauro Pezzè & Michal Young a c c Ch 5, slide 4 Graph Representations: labels and code • We can label nodes with the names or descriptions of the entities they represent. – If nodes a and b represent program regions containing assignment statements, we might draw the two nodes and an edge (a,b) connecting them in this way: x = y + z; a = f(x); (c) 2007 Mauro Pezzè & Michal Young Ch 5, slide .