Relevant Mutants.
- Not all surviving mutants indicate weaknesses in tests.
- Not relevant surviving mutants (don’t signal any test weakness):
-
Ignore these ones:
- In dead code (unreachable code)
- In legacy seams (intentionally excluded from test execution).
- Code not used because of legacy seams (also intentional).
-
Mutants in superfluous code:
- They survive because the mutation did not change any behavior.
- Still useful 💰: signal a possible simplification (refactoring opportunity).
-
- Relevant surviving mutants 💰: reveal genuine gaps in the test suite
- e.g. missing boundaries, too lenient assertions, etc.
- Read Relevant Mutants.
