a pytest plugin for parallel and concurrent testing
This plugin makes it possible to run tests quickly using multiprocessing (parallelism) and multithreading (concurrency).
pytest-xdist is great to run tests that:
- aren't threadsafe
- perform poorly when multithreaded
- need state isolation
pytest-parallel is better for some use cases (like Selenium tests) that:
- can be threadsafe
- can use non-blocking IO for http requests to make it performant
- manage little or no state in the Python environment
pytest-xdist does parallelism while
pytest-parallel does parallelism and concurrency.
- Python3 version [3.6+]
- Unix or Mac for
- Unix, Mac, or Windows for
pip install pytest-parallel
workers(optional) - max workers (aka processes) to start. Can be a positive integer or
autowhich uses one worker per core. Defaults to 1.
tests-per-worker(optional) - max concurrent tests per worker. Can be a positive integer or
autowhich evenly divides tests among the workers up to 50 concurrent tests. Defaults to 1.
# runs 2 workers with 1 test per worker at a time pytest --workers 2 # runs 4 workers (assuming a quad-core machine) with 1 test per worker pytest --workers auto # runs 1 worker with 4 tests at a time pytest --tests-per-worker 4 # runs 1 worker with up to 50 tests at a time pytest --tests-per-worker auto # runs 2 workers with up to 50 tests per worker pytest --workers 2 --tests-per-worker auto
Beginning with Python 3.8, forking behavior is forced on macOS at the expense of safety.
Changed in version 3.8: On macOS, the spawn start method is now the default. The fork start method should be considered unsafe as it can lead to crashes of the subprocess. See bpo-33725.