Evaluating Test Effectiveness with Mutation Analysis

Hence, the majority of residual faults in a program is likely to be due to small (single token) variations at certain points in the structure of the program from the correct program (This particular assumption is called the Competent Programmer Hypothesis or the Finite Neighborhood Hypothesis). The key insight here is that, for a significant majority of such faults, test cases that can detect a single change in isolation is very likely to detect the larger composite fault that contains it. The idea is to simply generate all possible valid variants of the program that differs from the original by a small change (such as a single token change) (Such variants are called mutants).

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