rstest 0.2.1

A fast, pytest-compatible test runner: parallel by design, with built-in suite diagnostics

rstest

A fast, pytest-compatible test runner. Rust orchestration, your tests unchanged: same plugins, same fixtures, same outcomes — parallel by design, with built-in suite diagnostics (--doctor).

pip install rstest   # pre-release: install from a built wheel for now, see docs/getting-started/installation.md
rstest

Parallel by default (-n auto). Tests that can't run in parallel can be marked @pytest.mark.serial (they run exclusively, after the parallel phase), order-dependent suites can use --dist loadfile, and rstest -n 0 gives a single pytest session with byte-exact pytest semantics.

The compat contract: at -n 0, outcomes are byte-exact. In parallel modes, outcomes are preserved for parallel-safe tests; tests with hidden time/ordering/shared-state assumptions can flake under high concurrency — exactly as under pytest-xdist. rstest --doctor and lower -n values help find and contain them; @pytest.mark.serial is the escape hatch.

Highlights:

• Drop-in: forwards the pytest flag surface; runs conftest, fixtures, parametrize, marks, and pytest plugins (pytest-django, pytest-asyncio, hypothesis, ...) through a vendored pytest core.
• Parallel by design: test-granular work distribution with duration-aware scheduling; @pytest.mark.serial and --dist loadfile safety rails; crashed workers respawn without losing your run.
• rstest --doctor: wait-bound tests, parallel-floor analysis, fixture hotspots, slowest files.
• rstest --watch: instant reruns on save; changed test files rerun alone, source changes rerun only the tests the import graph says are affected.

License

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.