some new features

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

@@ -0,0 +1,100 @@
+import time
+
+import joblib
+import numpy as np
+import pytest
+from numpy.testing import assert_array_equal
+
+from sklearn import config_context, get_config
+from sklearn.compose import make_column_transformer
+from sklearn.datasets import load_iris
+from sklearn.ensemble import RandomForestClassifier
+from sklearn.model_selection import GridSearchCV
+from sklearn.pipeline import make_pipeline
+from sklearn.preprocessing import StandardScaler
+from sklearn.utils.parallel import Parallel, delayed
+
+
+def get_working_memory():
+    return get_config()["working_memory"]
+
+
+@pytest.mark.parametrize("n_jobs", [1, 2])
+@pytest.mark.parametrize("backend", ["loky", "threading", "multiprocessing"])
+def test_configuration_passes_through_to_joblib(n_jobs, backend):
+    # Tests that the global global configuration is passed to joblib jobs
+
+    with config_context(working_memory=123):
+        results = Parallel(n_jobs=n_jobs, backend=backend)(
+            delayed(get_working_memory)() for _ in range(2)
+        )
+
+    assert_array_equal(results, [123] * 2)
+
+
+def test_parallel_delayed_warnings():
+    """Informative warnings should be raised when mixing sklearn and joblib API"""
+    # We should issue a warning when one wants to use sklearn.utils.fixes.Parallel
+    # with joblib.delayed. The config will not be propagated to the workers.
+    warn_msg = "`sklearn.utils.parallel.Parallel` needs to be used in conjunction"
+    with pytest.warns(UserWarning, match=warn_msg) as records:
+        Parallel()(joblib.delayed(time.sleep)(0) for _ in range(10))
+    assert len(records) == 10
+
+    # We should issue a warning if one wants to use sklearn.utils.fixes.delayed with
+    # joblib.Parallel
+    warn_msg = (
+        "`sklearn.utils.parallel.delayed` should be used with "
+        "`sklearn.utils.parallel.Parallel` to make it possible to propagate"
+    )
+    with pytest.warns(UserWarning, match=warn_msg) as records:
+        joblib.Parallel()(delayed(time.sleep)(0) for _ in range(10))
+    assert len(records) == 10
+
+
+@pytest.mark.parametrize("n_jobs", [1, 2])
+def test_dispatch_config_parallel(n_jobs):
+    """Check that we properly dispatch the configuration in parallel processing.
+
+    Non-regression test for:
+    https://github.com/scikit-learn/scikit-learn/issues/25239
+    """
+    pd = pytest.importorskip("pandas")
+    iris = load_iris(as_frame=True)
+
+    class TransformerRequiredDataFrame(StandardScaler):
+        def fit(self, X, y=None):
+            assert isinstance(X, pd.DataFrame), "X should be a DataFrame"
+            return super().fit(X, y)
+
+        def transform(self, X, y=None):
+            assert isinstance(X, pd.DataFrame), "X should be a DataFrame"
+            return super().transform(X, y)
+
+    dropper = make_column_transformer(
+        ("drop", [0]),
+        remainder="passthrough",
+        n_jobs=n_jobs,
+    )
+    param_grid = {"randomforestclassifier__max_depth": [1, 2, 3]}
+    search_cv = GridSearchCV(
+        make_pipeline(
+            dropper,
+            TransformerRequiredDataFrame(),
+            RandomForestClassifier(n_estimators=5, n_jobs=n_jobs),
+        ),
+        param_grid,
+        cv=5,
+        n_jobs=n_jobs,
+        error_score="raise",  # this search should not fail
+    )
+
+    # make sure that `fit` would fail in case we don't request dataframe
+    with pytest.raises(AssertionError, match="X should be a DataFrame"):
+        search_cv.fit(iris.data, iris.target)
+
+    with config_context(transform_output="pandas"):
+        # we expect each intermediate steps to output a DataFrame
+        search_cv.fit(iris.data, iris.target)
+
+    assert not np.isnan(search_cv.cv_results_["mean_test_score"]).any()