Applying Testing to Requirements Inspection for Software Quality Assurance

eveloping software systems involves a series of activities where there are many opportunities to make errors. Such errors may occur at an early stage of the development process where user requirements are incorrectly or incompletely specified, and also in subsequent stages when design and programming faults are introduced. Thus, software development should always be accompanied by quality assurance (QA) activities. Two common QA activities are requirements inspection and software testing (otherwise simply known as testing), which are often used in different phases of the software development life cycle (SDLC) . Traditionally, requirements inspection is performed at an early stage of SDLC to reveal defects in a requirements specification (thereafter simply referred to as a specification). On the other hand, testing is commonly done at a later stage of SDLC to look for program faults after coding. Because their purposes are different, requirements inspection and testing are often treated as “separate” and “unrelated” tasks by software practitioners. In recent years, many researchers have proposed to apply testing techniques to requirements inspection at an initial phase of the SDLC. 15 The idea is that generating test cases from a specification may uncover requirements defects well before programming starts. Thus, the possibility of inadvertently developing software based on an incorrect specification can be reduced. The benefits of such proposals are particularly prominent for large-scale projects where the specifications are complicated and may easily contain many requirements defects, and the costs of repairing these defects at the late stages of the SDLC are typically tens or hundreds of times greater than if the defects are corrected early. 6, 14 To support this proposal, we shall describe a method of applying testing techniques to requirements inspection, with a view to improving the quality of the specification before software design commences. But before the discussion, we first outline the basic concepts of requirements inspection and testing.