What method modifies a program to create small variations and tests these variations for correct behavior?

Mutation testing is a method that systematically modifies a program's source code to introduce small changes, termed "mutations." The primary goal of this approach is to assess the effectiveness of test cases by determining whether they can detect the changes made. In practice, it involves creating variants of the original program—often by making minor modifications to the code, such as altering logical operators or changing conditional statements.

The essence of mutation testing lies in evaluating whether existing test suites can fail when faced with these mutations. If the test cases detect the mutations and generate failures, it indicates that the tests are effective at identifying bugs or issues. Conversely, if the tests pass despite these changes, it suggests that the test suite may not cover all scenarios, leading to potential gaps in the verification of software integrity.

This technique is particularly useful in improving the robustness of the testing process, ensuring that the test cases not only verify functionality but also highlight areas where the code may be vulnerable or not adequately tested. Thus, mutation testing serves as a powerful approach to improve software quality through enhanced test case development and evaluation.