library packages

.venv/lib/python3.12/site-packages/sklearn/tests/random_seed.py

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