What problem does it solve? Rust developers often struggle with organizing test modules, mocking trait dependencies, generating edge-case inputs, and measuring code coverage. This Skill provides structured guidance for the full Rust testing workflow, from basic #[test] functions to property-based testing and CI-ready coverage reports. ## Core Features & Use Cases - Test Organization & Assertions: Covers #[cfg(test)] unit tests, tests/ directory integration tests, doc tests, assert! macro selection, #[should_panic], and Result<()> test patterns. - Mocking & Property Testing: Uses mockall to mock trait dependencies and proptest to automatically generate boundary-case inputs that verify code invariants. - Coverage & Fast Execution: Generates coverage reports with cargo-llvm-cov (with --fail-under-lines thresholds) and accelerates large test suites with cargo-nextest. - Use Case: When building a Rust service that depends on a database repository trait, use mockall to isolate the business logic, proptest to verify invariants like reverse involution, and cargo-llvm-cov to enforce an 80% line coverage gate in CI. ## Quick Start Ask the AI to write unit tests with mockall mocks and proptest property tests for your Rust crate, then set up cargo-llvm-cov coverage reporting.
