Minmal fix to remove side effects in sklearn/tests/test_pipeline.py

ogrisel · ogrisel · commit a7a15bf824fc · 2024-07-30T17:04:23.000+02:00
diff --git a/sklearn/tests/test_pipeline.py b/sklearn/tests/test_pipeline.py
@@ -52,7 +52,13 @@
 from sklearn.utils.fixes import CSR_CONTAINERS
 from sklearn.utils.validation import check_is_fitted
 
+# Load a shared tests data sets for the tests in this module. Mark them
+# read-only to avoid unintentional in-place modifications that would introduce
+# side-effects between tests.
 iris = load_iris()
+iris.data.flags.writeable = False
+iris.target.flags.writeable = False
+
 
 JUNK_FOOD_DOCS = (
     "the pizza pizza beer copyright",
@@ -499,7 +505,7 @@ def test_predict_methods_with_predict_params(method_name):
 @pytest.mark.parametrize("csr_container", CSR_CONTAINERS)
 def test_feature_union(csr_container):
     # basic sanity check for feature union
-    X = iris.data
+    X = iris.data.copy()
     X -= X.mean(axis=0)
     y = iris.target
     svd = TruncatedSVD(n_components=2, random_state=0)
@@ -1584,7 +1590,7 @@ def fit(self, X, y=None, **fit_params):
 def test_pipeline_missing_values_leniency():
     # check that pipeline let the missing values validation to
     # the underlying transformers and predictors.
-    X, y = iris.data, iris.target
+    X, y = iris.data.copy(), iris.target.copy()
     mask = np.random.choice([1, 0], X.shape, p=[0.1, 0.9]).astype(bool)
     X[mask] = np.nan
     pipe = make_pipeline(SimpleImputer(), LogisticRegression())
