Critical Analysis of the PIE Testability Technique

The work of Voas and colleagues has introduced, refined and applied the propagation, infection and execution (PIE) analysis technique for measuring testability of programs. The purpose of this paper is twofold: (1) to summarize and review the work done by Voas and others, and (2) to lay down a framework for automating the measurement of testability. In doing so, we introduce a prototype system, which uses the mutant schemata approach to calculate the infection estimate. The attempt, reported in this paper, to reproduce the results reported by Voas for one example, have shown that intermediate calculations are quite sensitive to minor variations in the parameters to the process, although the final testability results are in agreement.