pytest-ranking 0.2.0

A Pytest plugin for automatically prioritizing/ranking tests to speed up failure detection

pytest-ranking

A Pytest plugin for reducing failure detection time of your Python test suite with automated test prioritization/ranking.

This pytest plugin allows you to find failures faster and receive sooner debugging feedback from CI. It speed up test failure detection for your test suite by prioritizing the execution of tests that have shorter execution time and/or recently failed and/or more textually related to code change.

Installation

To install pytest-ranking via pip from PyPI:

pip install pytest-ranking

Usage

Pytest will automatically find the plugin and use it when you run pytest. You can use the default prioritization heuristic, which runs tests that have shorter execution time first by passing the --rank option:

pytest --rank

The terminal output will tell you the current configurations and runtime overhead of this plugin:

[pytest-ranking] Weights: 1-1-0
[pytest-ranking] History length: 30
[pytest-ranking] Number of files with new hashes: 0
[pytest-ranking] Change relatedness computation time (s): 0.0007872581481933594
[pytest-ranking] Test order computation time(s): 0.00020933151245117188

You can configure the weights of different prioritization heuristics by additionally passing the optional --rank-weight flag with formatted values:

pytest --rank --rank-weight=0-1-0

Weights are separated by hyphens -. The 1st weight is for running faster tests, the 2nd weight is for running recently failed tests, and the 3rd weight is for running tests more textually similar to the changed *.py files in the codebase since the last run. All weights must be integers or floats, and the sum of their sum will be normalized to 1. A higher weight means that a corresponding heuristic is favored. The default value is 1-0-0, meaning it entirely favors running faster tests.

You can also configure the maximum window size of previous test runs to compute the number of runs since a test had failed by additionally passing the optional --rank-hist-len flag as an integer input:

pytest --rank --rank-hist-len=30

You can make these options always apply by adding them to the addopts setting in your pytest.ini.

For example, create pytest.ini in the codebase root folder as such:

[pytest]
addopts = --rank --rank-weight=0-1-0 --rank-hist-len=30

Alternatively, you can create pytest.ini in the codebase root folder as such:

[pytest]
rank-weight=0-1-0
rank-hist-len=30

and run pytest --rank on command line.

Warning

Because pytest-ranking re-orders tests to speed up failure detection time, please disable other pytest plugins that enforeces other test orders, e.g., pytest-randomly, pytest-random-order, pytest-reverse.

Contributing

Contributions are very welcome. Tests can be run with tox.

License

Distributed under the terms of the MIT license, pytest-ranking is free and open source software.

Issues

If you encounter any problems, please file an issue or pull request along with a detailed description.