mutation-testing

Mutation testing measures smart contract test quality by injecting controlled bugs into Pact code and observing whether the test suite detects them. Surviving mutations indicate inadequate coverage and robustness gaps in the test suite.

Mutations applied to Pact code include arithmetic operator flips, logical condition negations, capability wrapper adjustments, and data access alterations. These deterministic mutations expose branch coverage issues and test data integrity.

To run a mutation testing session on a Pact project, execute the mutation operators against your code and run the test suite. The resulting report highlights which mutations are killed and which survive to fix test gaps.

Your Pact test suite passes but misses bugs because standard coverage metrics do not verify test assertions. Mutation testing addresses this by deliberately swapping logical conditions and removing capability wrappers to expose untested authorization logic.

Yes, you can validate authorization logic in Pact smart contracts through capability mutations. This process adjusts or removes capability wrappers during testing to ensure your test suite actively verifies authorization rules.