Software Testing: Concepts and Operations

2 Software Quality Attributes

When one buys a car, one may be interested in any number of quality attributes, including purchase price, maintenance cost, reliability, safety, fuel efficiency (mpg), engine size/power, acceleration (0–60 mph), comfort, roominess, looks, noise level, trunk size, environmental impact, and so on. Likewise, a software product may feature many quality attributes, which we review briefly in this chapter, focusing in particular on those that may be of interest with respect to software testing. We distinguish between five categories of software quality attributes which are as follows:

• Functional attributes, which characterize the input/output behavior of the software product
• Operational attributes, which characterize the operational conditions of the software product
• Usability attributes, which characterize the extent to which the software product can be used and adapted to user needs
• Business attributes, which characterize the cost of developing, using, and evolving the software product
• Structural attributes, which characterize the internal structure of the software product

We consider these families of attributes in turn, in this chapter. For each attribute, we will present a definition and, possibly, a quantification (i.e., a way to measure the attribute quantitatively). This classification is not perfectly orthogonal, and many attributes may be listed in more than one category; but it helps us to define some structure in the set of attributes. ...