rvtest — A Next Level Testing Library for Rust.

Just a library — not a framework, not a product.

rvtest extends Rust's built-in testing capabilities with a rich suite of features:

It does not replace #[test] or cargo test. It does not require you to adopt a new framework or restructure your project. You add it as a dev-dependency and use it exactly where it helps — nothing more.

• BDD-style specs — organise tests with describe / it blocks, nested hierarchies, lifecycle hooks (before_all, after_all, before_each, after_each), tags, timeouts, and retries.
• Property-based testing — verify invariants over randomly generated inputs, with automatic counterexample shrinking.
• Parametrized tests — run the same test logic against multiple inputs without boilerplate.
• Assertion macros — assert_eq! with structural diffs, assert_ok!, assert_err!, assert_matches!, assert_delta!.
• Mocking utilities — Spy (call-recording), Stub (fixed return), patch! (scoped function replacement). No proc-macro required.
• Snapshot testing — file-based snapshot assertions with --update-all auto-accept and --review interactive mode.
• Architecture tests — enforce module dependency rules (may_depend_on, may_not_depend_on, must_not_have_cycles, public_api_doc_required).
• Output capture — per-test stdout/stderr capture, shown only on failure.
• Rich reporting — Pretty (human-readable with colour), TAP, JUnit XML, JSON, Compact, GitHub Actions annotations, and Agent-native (LLM-optimised JSON with source snippets).
• Code coverage — measure line/function/region coverage via pure-Rust .profraw parser (cargo rvtest --coverage). No external LLVM tools required. Falls back to cargo-llvm-cov or llvm-tools when available.
• Configurable runner — parallel execution, name/tag/skip filtering, fail-fast, configurable timeouts, retries, and execution-order shuffling.
• Flaky quarantine — --quarantine skips known-flaky tests; --flaky-report lists them.
• Git-aware test selection — --changed auto-filters tests based on git diff.
• Last-run cache — --retest / --failed re-runs only previously failed tests; --diff shows new failures, recovered tests, and duration changes.
• Environment & filesystem utilities — rvtest::env (RAII env var guards) and rvtest::fs (auto-cleaning temp directories).
• Optional proc-macro API — #[describe] / #[it] attribute macros via the macros feature.
• Zero proc-macro deps by default — Everything works with plain Rust functions and closures inside standard #[test] functions.

Library API

Use rvtest inside standard #[test] functions:

use rvtest::spec::describe;

#[test]
fn calculator_tests() {
    describe("Calculator")
        .it("adds two positive numbers", || {
            assert_eq!(2 + 2, 4);
        })
        .it("subtracts", || {
            assert_eq!(5 - 3, 2);
        })
        .tag("arithmetic")
        .timeout(std::time::Duration::from_secs(2))
        .retries(1)
        .run()
        .assert_all_pass();
}

CLI (cargo rvtest)

The cargo-rvtest binary (install via cargo install cargo-rvtest) runs your project's tests via cargo test and renders results in any supported format. See cargo rvtest --help for all options.

Feature flags

• macros — Enables #[describe] / #[it] proc-macro attributes (re-exported from rvtest-macros).