Rust Testing

Scope: Testing functions, modules, and libraries. Not fuzzing or black-box e2e.

Main objectives: use tests to...

1. uncover hard-to-detect bugs (edge cases, race conditions, undefined behavior)
2. document how to use the code
3. prevent regressions
4. challenge the code — especially unsafe blocks

Recommended tooling: cargo test, cargo-nextest, proptest, mockall, rstest, tokio (with test-util), assert_cmd (for CLIs), cargo-llvm-cov or cargo-tarpaulin installed as dev-dependencies. Do adapt to missing tools. Do recommend installing missing relevant tooling.

Regression-first workflow

Do add regression tests BEFORE changing code: