85 lines
3.2 KiB
Python
85 lines
3.2 KiB
Python
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"""global_random_seed fixture
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The goal of this fixture is to prevent tests that use it to be sensitive
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to a specific seed value while still being deterministic by default.
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See the documentation for the SKLEARN_TESTS_GLOBAL_RANDOM_SEED
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variable for insrtuctions on how to use this fixture.
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https://scikit-learn.org/dev/computing/parallelism.html#sklearn-tests-global-random-seed
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"""
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from os import environ
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from random import Random
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import pytest
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# Passes the main worker's random seeds to workers
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class XDistHooks:
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def pytest_configure_node(self, node) -> None:
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random_seeds = node.config.getoption("random_seeds")
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node.workerinput["random_seeds"] = random_seeds
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def pytest_configure(config):
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if config.pluginmanager.hasplugin("xdist"):
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config.pluginmanager.register(XDistHooks())
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RANDOM_SEED_RANGE = list(range(100)) # All seeds in [0, 99] should be valid.
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random_seed_var = environ.get("SKLEARN_TESTS_GLOBAL_RANDOM_SEED")
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if hasattr(config, "workerinput") and "random_seeds" in config.workerinput:
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# Set worker random seed from seed generated from main process
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random_seeds = config.workerinput["random_seeds"]
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elif random_seed_var is None:
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# This is the way.
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random_seeds = [42]
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elif random_seed_var == "any":
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# Pick-up one seed at random in the range of admissible random seeds.
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random_seeds = [Random().choice(RANDOM_SEED_RANGE)]
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elif random_seed_var == "all":
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random_seeds = RANDOM_SEED_RANGE
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else:
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if "-" in random_seed_var:
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start, stop = random_seed_var.split("-")
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random_seeds = list(range(int(start), int(stop) + 1))
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else:
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random_seeds = [int(random_seed_var)]
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if min(random_seeds) < 0 or max(random_seeds) > 99:
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raise ValueError(
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"The value(s) of the environment variable "
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"SKLEARN_TESTS_GLOBAL_RANDOM_SEED must be in the range [0, 99] "
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f"(or 'any' or 'all'), got: {random_seed_var}"
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)
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config.option.random_seeds = random_seeds
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class GlobalRandomSeedPlugin:
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@pytest.fixture(params=random_seeds)
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def global_random_seed(self, request):
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"""Fixture to ask for a random yet controllable random seed.
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All tests that use this fixture accept the contract that they should
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deterministically pass for any seed value from 0 to 99 included.
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See the documentation for the SKLEARN_TESTS_GLOBAL_RANDOM_SEED
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variable for insrtuctions on how to use this fixture.
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https://scikit-learn.org/dev/computing/parallelism.html#sklearn-tests-global-random-seed
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"""
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yield request.param
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config.pluginmanager.register(GlobalRandomSeedPlugin())
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def pytest_report_header(config):
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random_seed_var = environ.get("SKLEARN_TESTS_GLOBAL_RANDOM_SEED")
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if random_seed_var == "any":
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return [
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"To reproduce this test run, set the following environment variable:",
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f' SKLEARN_TESTS_GLOBAL_RANDOM_SEED="{config.option.random_seeds[0]}"',
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(
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"See: https://scikit-learn.org/dev/computing/parallelism.html"
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"#sklearn-tests-global-random-seed"
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),
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]
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