What problem does it solve? Code changes often ship with tests that pass but do not actually prove the new behavior, leaving regressions undetected. This Skill audits Rust tests against the behavioral contracts in a diff to find coverage gaps, weak assertions, and lost protections. ## Core Features & Use Cases - Coverage and regression analysis: Traces changed behavior to its tests, identifies plausible regressions the existing suite would accept, and flags removed tests, broadened matchers, or new #[ignore] gates that silently drop protection. - Assertion and oracle quality checks: Detects tautological assertions, imprecise float comparisons, overly broad #[should_panic] tests, and mocks that bypass the behavior under test. - Isolation and determinism review: Examines shared state, environment dependencies, async interleavings, and feature-gated behavior for nondeterministic failures. - Use Case: After refactoring error handling in a Rust service, ask for a test quality review of the working changes to learn which error variants lack regression tests before merging. ## Quick Start Ask the agent to review whether the tests in your current staged and unstaged Rust changes actually prove the changed behavior, and to report findings with file locations without editing code.
