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Karva

A Python test framework, written in Rust.

Run Python tests in parallel.

In alpha. Check compatibility before migrating.

Run your first test Read the guide

Get started 
uv add --dev karvauv run karva test

Benchmarks

Results depend on your suite and machine.

karva2.6 seconds2.60s
pytest-xdist60.5 seconds60.50s
pytest92.2 seconds92.20s
Workload: approximately 250,000 tests · Machine: 14 cores · Benchmark project

Built in

Parallel executionSeparate Python workers FilteringSelect tests with expressions Watch modeRerun after source changes CoverageNative line coverage SnapshotsFile and inline snapshots FixturesShare setup and teardown