Software Testing Techniques 2E

Software Testing Techniques 2E
International Thomson Computer Press; 2nd edition | English | ISBN: 1850328803 | 580 pages | June 1990 | CHM | 4Mb

Every professional and commercial software development organization spends a great deal of time in the testing and validation of their software. The testing process, driven either by legal or financial requirements, can be expensive and may thwart the planned deployment of the application. Many studies indicate that the testing process can even take three times as long as the actual coding itself. Indeed, software development done under the ISO 9000 or FDA auspices can be extremely time intensive.

This book gives a lengthy and fairly comprehensive overview of software testing that emphasizes formal models for testing. In the introduction, the author gives a general overview of the testing process and the reasons and goals for testing. He carefully distinguishes between testing and debugging, and advocates these as separate activities. Testing according to the author is done to find bugs; whereas debugging is done to find the origin of the bugs and fix them. The author characterizes testing as either functional or structural. Functional testing treats the program from the user's point of view, with inputs given to the program, and then the outputs are checked for conformance to a specified reference. Structural testing examines how the program is implemented, in terms of programming style, design, etc. The notion of an oracle is defined as any program or process that specifies the expected outcome of a collection of tests. The author clearly identifies and characterizes the different types of tests that arise in development organizations, such as unit testing, regression testing, stress testing, and integration testing.

In chapter 2, the author classifies the different types of bugs that could arise in program development. Bugs are classified according to functional, structural, data, coding, system, and design and test bugs. He stresses the need to not have a religious attitude about bugs, namely that all software will have them to some degree, and therefore it is the quality measure of the software that is important in deploying the application. If a minor bug requires a major software rewrite for example, it would not be advantageous to fix this bug.

Chapter 3 takes up the notion of path testing, which, according to the author, is based on the use of the program's flow control. The tester selects a set of test paths through the program with the goal of executing every statement and branch of the program at least once. The author summarizes well the flowgraph and process block techniques used to implement path testing.

In chapter 4, the author introduces the concept of a transaction flow as a representation of a system's processing. The flowgraphs developed in chapter 3 are used here to create a transaction flowgraph for functional testing. The transaction flow representation gives a way to model the system's behavior. The author's treatment here is very detailed, and he gives several useful tips on how to conduct this kind of testing.

The next chapter covers the topic of data-flow testing, where again flowgraphs are used, but this time the focus is on exploring the things that can happen to data. Data objects should be initialized prior to program execution, and selecting paths to insure this is the goal of data testing. The author does a good job of defining and characterizing data anomalies, and the strategies employed in static and dynamic anomaly detection. This is followed by a good overview of domain testing in chapter 6. This kind of testing, more mathematical in nature than others, attempts to test whether the inputs to programs are fulfilling some prior classification or specification. The author uses concepts from vector spaces and convex geometry to describe domain testing.

In chapter 7, several attempts are discussed to quantify program complexity, such as Halstead's metrics and token counts. This chapter is somewhat more theoretical at first glance, but a lot of these ideas have found practical application in development, particularly the measures for subroutine nesting. This is followed in the next two chapters by more abstract discussion involving paths, regular expression, and syntax testing. The discussion however is useful, for it trains the reader about how to think about a program in more general, linguistic terms. Such thinking is always useful when attempting to show a particular program is acting in ways other than that which it was designed for.

Logic-based testing, via Boolean algebra, is the topic of chapter 10. The author uses Karnaugh-Veitch charts to reduce the algebraic manipulations to a useful graphical representation. Finite-state machines, so useful in all areas of software engineering, are the topic of chapter 11. The concepts are presented very effectively by the author, and the reader should take away an appreciation of how these constructions are employed in software testing.

The next chapter reads like one straight out of a book on discrete geometry, wherein graph matrices are employed to give matrix representations in software. Linked lists are used to represent the graphs in a computer, and it is shown how testing problems can be represented as a graph problem.

The last chapter discusses how to implement software testing based on the strategies discussed in the book. The three-phase test scenario is described, namely unit, integration, and system testing. An overview of commercial testing tools is also given, with CASE mentioned, but the author chooses not to review the actual packages, citing the dynamic nature of the commercial situation. However he does give a useful discussion of the different characteristics of current testing tools.

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