Eliminating products to test in a software product line

A Software Product Line (SPL) is a family of programs where each program is defined by a unique combination of features. Developing a set of programs with commonalities and variabilities in this way can significantly reduce both the time and cost of software development. However, as the number of programs may be exponential in the number of features, testing an SPL, the phase to which the majority of software development is dedicated, becomes especially challenging [12]. Indeed, scale is the biggest challenge in testing or checking the properties of programs in a product line. Even a product line with just 10 optional features has over a thousand (210) distinct programs. As an example of a situation where every program must be considered, suppose that every program of an SPL outputs a String that each feature might modify.