Mutation testing is an innovative approach in software testing that involves intentionally introducing small changes, or "mutations," to the source code of a program. The purpose? To test the effectiveness of your test cases and ensure that they can catch even the most subtle faults. In this article, we'll explore how mutation testing works using Python as our language of choice.
What Is Mutation Testing?
Mutation testing starts with a program that is already passing all its test cases. Then, we introduce slight modifications to the source code, creating what is known as "mutants." These mutants are slightly altered versions of the original program. The key idea is to run your existing test cases against these mutants. If a test case fails, it has successfully "killed" the mutant, indicating that the test case is effective. If all test cases pass, the mutant has survived, suggesting a potential gap in the test coverage.