rust-impl-testing

The Rust testing skill: how to write unit tests, integration tests, and doc tests; how Cargo's three test kinds map to file layout; how to use #[should_panic], #[ignore], and Result<(), E>-returning tests; how to run async tests with #[tokio::test]; when to switch from cargo test to cargo nextest run; and how to add property, snapshot, and benchmark testing on stable Rust.

Cross-references: [[rust-impl-cargo-project]] (the [profile.test] profile, [dev-dependencies], the test and bench fields), [[rust-impl-async-tokio]] (#[tokio::test] runtime selection), [[rust-syntax-async-await]] (calling .await in test bodies).

When to use this skill

• User writes #[test] functions, or wraps them in #[cfg(test)] mod tests { ... }.
• User asks where integration tests go (src/, tests/, examples/?).
• User writes doc tests in /// comments and one of them stops compiling.
• User wants negative tests via #[should_panic] or wants to skip slow tests via #[ignore].
• User writes an async fn test and gets a runtime panic.
• User wants a faster runner than cargo test, or per-test process isolation.
• User wants property-based, snapshot, or micro-benchmark coverage on stable Rust.

For Cargo's project layout, [dev-dependencies], and the [profile.test] / [profile.bench] profiles, see [[rust-impl-cargo-project]]. For tokio runtime details under #[tokio::test], see [[rust-impl-async-tokio]].