Rust unit-isolation lint (#44): an inline #[cfg(test)] mod may call only into
the unit under test — its parent module, reached via super::. A call out of
the test’s own module — into another first-party module (crate::…), an
external crate, or effectful std — is a violation. Inject a trait double
(hand-rolled or mockall) instead; the compiler checks the double.
Mutation testing for Rust (unit mutation --language rust, #201) — the rung
above coverage. A test that runs a line still passes if you delete its
assertions; a surviving mutant proves it. This module wraps
cargo-mutants: it runs the engine,
reads its outcomes.json, and reports the surviving mutants the suite failed
to catch.
Languages the integration-test lints support — its own set (Python,
TypeScript, Rust), distinct from the file-pairing colocated_test::Language,
so adding Rust here doesn’t touch the colocated-test/coverage rules.
The binary’s own clap command tree — the source of truth for which subcommands
it exposes. The workflow guard (#92) checks a workflow’s invocations against
it, so a renamed or removed subcommand is caught the moment they diverge.