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+"""Testing for the VotingClassifier and VotingRegressor"""
+
+import re
+
+import numpy as np
+import pytest
+
+from sklearn import config_context, datasets
+from sklearn.base import BaseEstimator, ClassifierMixin, clone
+from sklearn.calibration import CalibratedClassifierCV
+from sklearn.datasets import make_multilabel_classification
+from sklearn.dummy import DummyRegressor
+from sklearn.ensemble import (
+    RandomForestClassifier,
+    RandomForestRegressor,
+    VotingClassifier,
+    VotingRegressor,
+)
+from sklearn.exceptions import NotFittedError
+from sklearn.linear_model import LinearRegression, LogisticRegression
+from sklearn.model_selection import GridSearchCV, cross_val_score, train_test_split
+from sklearn.multiclass import OneVsRestClassifier
+from sklearn.naive_bayes import GaussianNB
+from sklearn.neighbors import KNeighborsClassifier
+from sklearn.preprocessing import StandardScaler
+from sklearn.svm import SVC
+from sklearn.tests.metadata_routing_common import (
+    ConsumingClassifier,
+    ConsumingRegressor,
+    _Registry,
+    check_recorded_metadata,
+)
+from sklearn.tree import DecisionTreeClassifier, DecisionTreeRegressor
+from sklearn.utils._testing import (
+    assert_almost_equal,
+    assert_array_almost_equal,
+    assert_array_equal,
+)
+
+# Load datasets
+iris = datasets.load_iris()
+X, y = iris.data[:, 1:3], iris.target
+# Scaled to solve ConvergenceWarning throw by Logistic Regression
+X_scaled = StandardScaler().fit_transform(X)
+
+X_r, y_r = datasets.load_diabetes(return_X_y=True)
+
+
+@pytest.mark.parametrize(
+    "params, err_msg",
+    [
+        (
+            {"estimators": []},
+            "Invalid 'estimators' attribute, 'estimators' should be a non-empty list",
+        ),
+        (
+            {"estimators": [LogisticRegression()]},
+            "Invalid 'estimators' attribute, 'estimators' should be a non-empty list",
+        ),
+        (
+            {"estimators": [(213, LogisticRegression())]},
+            "Invalid 'estimators' attribute, 'estimators' should be a non-empty list",
+        ),
+        (
+            {"estimators": [("lr", LogisticRegression())], "weights": [1, 2]},
+            "Number of `estimators` and weights must be equal",
+        ),
+    ],
+)
+def test_voting_classifier_estimator_init(params, err_msg):
+    ensemble = VotingClassifier(**params)
+    with pytest.raises(ValueError, match=err_msg):
+        ensemble.fit(X, y)
+
+
+def test_predictproba_hardvoting():
+    eclf = VotingClassifier(
+        estimators=[("lr1", LogisticRegression()), ("lr2", LogisticRegression())],
+        voting="hard",
+    )
+
+    inner_msg = "predict_proba is not available when voting='hard'"
+    outer_msg = "'VotingClassifier' has no attribute 'predict_proba'"
+    with pytest.raises(AttributeError, match=outer_msg) as exec_info:
+        eclf.predict_proba
+    assert isinstance(exec_info.value.__cause__, AttributeError)
+    assert inner_msg in str(exec_info.value.__cause__)
+
+    assert not hasattr(eclf, "predict_proba")
+    eclf.fit(X_scaled, y)
+    assert not hasattr(eclf, "predict_proba")
+
+
+def test_notfitted():
+    eclf = VotingClassifier(
+        estimators=[("lr1", LogisticRegression()), ("lr2", LogisticRegression())],
+        voting="soft",
+    )
+    ereg = VotingRegressor([("dr", DummyRegressor())])
+    msg = (
+        "This %s instance is not fitted yet. Call 'fit'"
+        " with appropriate arguments before using this estimator."
+    )
+    with pytest.raises(NotFittedError, match=msg % "VotingClassifier"):
+        eclf.predict(X)
+    with pytest.raises(NotFittedError, match=msg % "VotingClassifier"):
+        eclf.predict_proba(X)
+    with pytest.raises(NotFittedError, match=msg % "VotingClassifier"):
+        eclf.transform(X)
+    with pytest.raises(NotFittedError, match=msg % "VotingRegressor"):
+        ereg.predict(X_r)
+    with pytest.raises(NotFittedError, match=msg % "VotingRegressor"):
+        ereg.transform(X_r)
+
+
+def test_majority_label_iris(global_random_seed):
+    """Check classification by majority label on dataset iris."""
+    clf1 = LogisticRegression(random_state=global_random_seed)
+    clf2 = RandomForestClassifier(n_estimators=10, random_state=global_random_seed)
+    clf3 = GaussianNB()
+    eclf = VotingClassifier(
+        estimators=[("lr", clf1), ("rf", clf2), ("gnb", clf3)], voting="hard"
+    )
+    scores = cross_val_score(eclf, X, y, scoring="accuracy")
+
+    assert scores.mean() >= 0.9
+
+
+def test_tie_situation():
+    """Check voting classifier selects smaller class label in tie situation."""
+    clf1 = LogisticRegression(random_state=123)
+    clf2 = RandomForestClassifier(random_state=123)
+    eclf = VotingClassifier(estimators=[("lr", clf1), ("rf", clf2)], voting="hard")
+    assert clf1.fit(X, y).predict(X)[52] == 2
+    assert clf2.fit(X, y).predict(X)[52] == 1
+    assert eclf.fit(X, y).predict(X)[52] == 1
+
+
+def test_weights_iris(global_random_seed):
+    """Check classification by average probabilities on dataset iris."""
+    clf1 = LogisticRegression(random_state=global_random_seed)
+    clf2 = RandomForestClassifier(n_estimators=10, random_state=global_random_seed)
+    clf3 = GaussianNB()
+    eclf = VotingClassifier(
+        estimators=[("lr", clf1), ("rf", clf2), ("gnb", clf3)],
+        voting="soft",
+        weights=[1, 2, 10],
+    )
+    scores = cross_val_score(eclf, X_scaled, y, scoring="accuracy")
+    assert scores.mean() >= 0.9
+
+
+def test_weights_regressor():
+    """Check weighted average regression prediction on diabetes dataset."""
+    reg1 = DummyRegressor(strategy="mean")
+    reg2 = DummyRegressor(strategy="median")
+    reg3 = DummyRegressor(strategy="quantile", quantile=0.2)
+    ereg = VotingRegressor(
+        [("mean", reg1), ("median", reg2), ("quantile", reg3)], weights=[1, 2, 10]
+    )
+
+    X_r_train, X_r_test, y_r_train, y_r_test = train_test_split(
+        X_r, y_r, test_size=0.25
+    )
+
+    reg1_pred = reg1.fit(X_r_train, y_r_train).predict(X_r_test)
+    reg2_pred = reg2.fit(X_r_train, y_r_train).predict(X_r_test)
+    reg3_pred = reg3.fit(X_r_train, y_r_train).predict(X_r_test)
+    ereg_pred = ereg.fit(X_r_train, y_r_train).predict(X_r_test)
+
+    avg = np.average(
+        np.asarray([reg1_pred, reg2_pred, reg3_pred]), axis=0, weights=[1, 2, 10]
+    )
+    assert_almost_equal(ereg_pred, avg, decimal=2)
+
+    ereg_weights_none = VotingRegressor(
+        [("mean", reg1), ("median", reg2), ("quantile", reg3)], weights=None
+    )
+    ereg_weights_equal = VotingRegressor(
+        [("mean", reg1), ("median", reg2), ("quantile", reg3)], weights=[1, 1, 1]
+    )
+    ereg_weights_none.fit(X_r_train, y_r_train)
+    ereg_weights_equal.fit(X_r_train, y_r_train)
+    ereg_none_pred = ereg_weights_none.predict(X_r_test)
+    ereg_equal_pred = ereg_weights_equal.predict(X_r_test)
+    assert_almost_equal(ereg_none_pred, ereg_equal_pred, decimal=2)
+
+
+def test_predict_on_toy_problem(global_random_seed):
+    """Manually check predicted class labels for toy dataset."""
+    clf1 = LogisticRegression(random_state=global_random_seed)
+    clf2 = RandomForestClassifier(n_estimators=10, random_state=global_random_seed)
+    clf3 = GaussianNB()
+
+    X = np.array(
+        [[-1.1, -1.5], [-1.2, -1.4], [-3.4, -2.2], [1.1, 1.2], [2.1, 1.4], [3.1, 2.3]]
+    )
+
+    y = np.array([1, 1, 1, 2, 2, 2])
+
+    assert_array_equal(clf1.fit(X, y).predict(X), [1, 1, 1, 2, 2, 2])
+    assert_array_equal(clf2.fit(X, y).predict(X), [1, 1, 1, 2, 2, 2])
+    assert_array_equal(clf3.fit(X, y).predict(X), [1, 1, 1, 2, 2, 2])
+
+    eclf = VotingClassifier(
+        estimators=[("lr", clf1), ("rf", clf2), ("gnb", clf3)],
+        voting="hard",
+        weights=[1, 1, 1],
+    )
+    assert_array_equal(eclf.fit(X, y).predict(X), [1, 1, 1, 2, 2, 2])
+
+    eclf = VotingClassifier(
+        estimators=[("lr", clf1), ("rf", clf2), ("gnb", clf3)],
+        voting="soft",
+        weights=[1, 1, 1],
+    )
+    assert_array_equal(eclf.fit(X, y).predict(X), [1, 1, 1, 2, 2, 2])
+
+
+def test_predict_proba_on_toy_problem():
+    """Calculate predicted probabilities on toy dataset."""
+    clf1 = LogisticRegression(random_state=123)
+    clf2 = RandomForestClassifier(random_state=123)
+    clf3 = GaussianNB()
+    X = np.array([[-1.1, -1.5], [-1.2, -1.4], [-3.4, -2.2], [1.1, 1.2]])
+    y = np.array([1, 1, 2, 2])
+
+    clf1_res = np.array(
+        [
+            [0.59790391, 0.40209609],
+            [0.57622162, 0.42377838],
+            [0.50728456, 0.49271544],
+            [0.40241774, 0.59758226],
+        ]
+    )
+
+    clf2_res = np.array([[0.8, 0.2], [0.8, 0.2], [0.2, 0.8], [0.3, 0.7]])
+
+    clf3_res = np.array(
+        [[0.9985082, 0.0014918], [0.99845843, 0.00154157], [0.0, 1.0], [0.0, 1.0]]
+    )
+
+    t00 = (2 * clf1_res[0][0] + clf2_res[0][0] + clf3_res[0][0]) / 4
+    t11 = (2 * clf1_res[1][1] + clf2_res[1][1] + clf3_res[1][1]) / 4
+    t21 = (2 * clf1_res[2][1] + clf2_res[2][1] + clf3_res[2][1]) / 4
+    t31 = (2 * clf1_res[3][1] + clf2_res[3][1] + clf3_res[3][1]) / 4
+
+    eclf = VotingClassifier(
+        estimators=[("lr", clf1), ("rf", clf2), ("gnb", clf3)],
+        voting="soft",
+        weights=[2, 1, 1],
+    )
+    eclf_res = eclf.fit(X, y).predict_proba(X)
+
+    assert_almost_equal(t00, eclf_res[0][0], decimal=1)
+    assert_almost_equal(t11, eclf_res[1][1], decimal=1)
+    assert_almost_equal(t21, eclf_res[2][1], decimal=1)
+    assert_almost_equal(t31, eclf_res[3][1], decimal=1)
+
+    inner_msg = "predict_proba is not available when voting='hard'"
+    outer_msg = "'VotingClassifier' has no attribute 'predict_proba'"
+    with pytest.raises(AttributeError, match=outer_msg) as exec_info:
+        eclf = VotingClassifier(
+            estimators=[("lr", clf1), ("rf", clf2), ("gnb", clf3)], voting="hard"
+        )
+        eclf.fit(X, y).predict_proba(X)
+
+    assert isinstance(exec_info.value.__cause__, AttributeError)
+    assert inner_msg in str(exec_info.value.__cause__)
+
+
+def test_multilabel():
+    """Check if error is raised for multilabel classification."""
+    X, y = make_multilabel_classification(
+        n_classes=2, n_labels=1, allow_unlabeled=False, random_state=123
+    )
+    clf = OneVsRestClassifier(SVC(kernel="linear"))
+
+    eclf = VotingClassifier(estimators=[("ovr", clf)], voting="hard")
+
+    try:
+        eclf.fit(X, y)
+    except NotImplementedError:
+        return
+
+
+def test_gridsearch():
+    """Check GridSearch support."""
+    clf1 = LogisticRegression(random_state=1)
+    clf2 = RandomForestClassifier(random_state=1, n_estimators=3)
+    clf3 = GaussianNB()
+    eclf = VotingClassifier(
+        estimators=[("lr", clf1), ("rf", clf2), ("gnb", clf3)], voting="soft"
+    )
+
+    params = {
+        "lr__C": [1.0, 100.0],
+        "voting": ["soft", "hard"],
+        "weights": [[0.5, 0.5, 0.5], [1.0, 0.5, 0.5]],
+    }
+
+    grid = GridSearchCV(estimator=eclf, param_grid=params, cv=2)
+    grid.fit(X_scaled, y)
+
+
+def test_parallel_fit(global_random_seed):
+    """Check parallel backend of VotingClassifier on toy dataset."""
+    clf1 = LogisticRegression(random_state=global_random_seed)
+    clf2 = RandomForestClassifier(n_estimators=10, random_state=global_random_seed)
+    clf3 = GaussianNB()
+    X = np.array([[-1.1, -1.5], [-1.2, -1.4], [-3.4, -2.2], [1.1, 1.2]])
+    y = np.array([1, 1, 2, 2])
+
+    eclf1 = VotingClassifier(
+        estimators=[("lr", clf1), ("rf", clf2), ("gnb", clf3)], voting="soft", n_jobs=1
+    ).fit(X, y)
+    eclf2 = VotingClassifier(
+        estimators=[("lr", clf1), ("rf", clf2), ("gnb", clf3)], voting="soft", n_jobs=2
+    ).fit(X, y)
+
+    assert_array_equal(eclf1.predict(X), eclf2.predict(X))
+    assert_array_almost_equal(eclf1.predict_proba(X), eclf2.predict_proba(X))
+
+
+def test_sample_weight(global_random_seed):
+    """Tests sample_weight parameter of VotingClassifier"""
+    clf1 = LogisticRegression(random_state=global_random_seed)
+    clf2 = RandomForestClassifier(n_estimators=10, random_state=global_random_seed)
+    clf3 = CalibratedClassifierCV(SVC(random_state=global_random_seed), ensemble=False)
+    eclf1 = VotingClassifier(
+        estimators=[("lr", clf1), ("rf", clf2), ("svc", clf3)], voting="soft"
+    ).fit(X_scaled, y, sample_weight=np.ones((len(y),)))
+    eclf2 = VotingClassifier(
+        estimators=[("lr", clf1), ("rf", clf2), ("svc", clf3)], voting="soft"
+    ).fit(X_scaled, y)
+    assert_array_equal(eclf1.predict(X_scaled), eclf2.predict(X_scaled))
+    assert_array_almost_equal(
+        eclf1.predict_proba(X_scaled), eclf2.predict_proba(X_scaled)
+    )
+    sample_weight = np.random.RandomState(global_random_seed).uniform(size=(len(y),))
+    eclf3 = VotingClassifier(estimators=[("lr", clf1)], voting="soft")
+    eclf3.fit(X_scaled, y, sample_weight=sample_weight)
+    clf1.fit(X_scaled, y, sample_weight)
+    assert_array_equal(eclf3.predict(X_scaled), clf1.predict(X_scaled))
+    assert_array_almost_equal(
+        eclf3.predict_proba(X_scaled), clf1.predict_proba(X_scaled)
+    )
+
+    # check that an error is raised and indicative if sample_weight is not
+    # supported.
+    clf4 = KNeighborsClassifier()
+    eclf3 = VotingClassifier(
+        estimators=[("lr", clf1), ("svc", clf3), ("knn", clf4)], voting="soft"
+    )
+    msg = "Underlying estimator KNeighborsClassifier does not support sample weights."
+    with pytest.raises(TypeError, match=msg):
+        eclf3.fit(X_scaled, y, sample_weight=sample_weight)
+
+    # check that _fit_single_estimator will raise the right error
+    # it should raise the original error if this is not linked to sample_weight
+    class ClassifierErrorFit(ClassifierMixin, BaseEstimator):
+        def fit(self, X_scaled, y, sample_weight):
+            raise TypeError("Error unrelated to sample_weight.")
+
+    clf = ClassifierErrorFit()
+    with pytest.raises(TypeError, match="Error unrelated to sample_weight"):
+        clf.fit(X_scaled, y, sample_weight=sample_weight)
+
+
+def test_sample_weight_kwargs():
+    """Check that VotingClassifier passes sample_weight as kwargs"""
+
+    class MockClassifier(ClassifierMixin, BaseEstimator):
+        """Mock Classifier to check that sample_weight is received as kwargs"""
+
+        def fit(self, X, y, *args, **sample_weight):
+            assert "sample_weight" in sample_weight
+
+    clf = MockClassifier()
+    eclf = VotingClassifier(estimators=[("mock", clf)], voting="soft")
+
+    # Should not raise an error.
+    eclf.fit(X, y, sample_weight=np.ones((len(y),)))
+
+
+def test_voting_classifier_set_params(global_random_seed):
+    # check equivalence in the output when setting underlying estimators
+    clf1 = LogisticRegression(random_state=global_random_seed)
+    clf2 = RandomForestClassifier(
+        n_estimators=10, random_state=global_random_seed, max_depth=None
+    )
+    clf3 = GaussianNB()
+
+    eclf1 = VotingClassifier(
+        [("lr", clf1), ("rf", clf2)], voting="soft", weights=[1, 2]
+    ).fit(X_scaled, y)
+    eclf2 = VotingClassifier(
+        [("lr", clf1), ("nb", clf3)], voting="soft", weights=[1, 2]
+    )
+    eclf2.set_params(nb=clf2).fit(X_scaled, y)
+
+    assert_array_equal(eclf1.predict(X_scaled), eclf2.predict(X_scaled))
+    assert_array_almost_equal(
+        eclf1.predict_proba(X_scaled), eclf2.predict_proba(X_scaled)
+    )
+    assert eclf2.estimators[0][1].get_params() == clf1.get_params()
+    assert eclf2.estimators[1][1].get_params() == clf2.get_params()
+
+
+def test_set_estimator_drop():
+    # VotingClassifier set_params should be able to set estimators as drop
+    # Test predict
+    clf1 = LogisticRegression(random_state=123)
+    clf2 = RandomForestClassifier(n_estimators=10, random_state=123)
+    clf3 = GaussianNB()
+    eclf1 = VotingClassifier(
+        estimators=[("lr", clf1), ("rf", clf2), ("nb", clf3)],
+        voting="hard",
+        weights=[1, 0, 0.5],
+    ).fit(X, y)
+
+    eclf2 = VotingClassifier(
+        estimators=[("lr", clf1), ("rf", clf2), ("nb", clf3)],
+        voting="hard",
+        weights=[1, 1, 0.5],
+    )
+    eclf2.set_params(rf="drop").fit(X, y)
+
+    assert_array_equal(eclf1.predict(X), eclf2.predict(X))
+
+    assert dict(eclf2.estimators)["rf"] == "drop"
+    assert len(eclf2.estimators_) == 2
+    assert all(
+        isinstance(est, (LogisticRegression, GaussianNB)) for est in eclf2.estimators_
+    )
+    assert eclf2.get_params()["rf"] == "drop"
+
+    eclf1.set_params(voting="soft").fit(X, y)
+    eclf2.set_params(voting="soft").fit(X, y)
+
+    assert_array_equal(eclf1.predict(X), eclf2.predict(X))
+    assert_array_almost_equal(eclf1.predict_proba(X), eclf2.predict_proba(X))
+    msg = "All estimators are dropped. At least one is required"
+    with pytest.raises(ValueError, match=msg):
+        eclf2.set_params(lr="drop", rf="drop", nb="drop").fit(X, y)
+
+    # Test soft voting transform
+    X1 = np.array([[1], [2]])
+    y1 = np.array([1, 2])
+    eclf1 = VotingClassifier(
+        estimators=[("rf", clf2), ("nb", clf3)],
+        voting="soft",
+        weights=[0, 0.5],
+        flatten_transform=False,
+    ).fit(X1, y1)
+
+    eclf2 = VotingClassifier(
+        estimators=[("rf", clf2), ("nb", clf3)],
+        voting="soft",
+        weights=[1, 0.5],
+        flatten_transform=False,
+    )
+    eclf2.set_params(rf="drop").fit(X1, y1)
+    assert_array_almost_equal(
+        eclf1.transform(X1),
+        np.array([[[0.7, 0.3], [0.3, 0.7]], [[1.0, 0.0], [0.0, 1.0]]]),
+    )
+    assert_array_almost_equal(eclf2.transform(X1), np.array([[[1.0, 0.0], [0.0, 1.0]]]))
+    eclf1.set_params(voting="hard")
+    eclf2.set_params(voting="hard")
+    assert_array_equal(eclf1.transform(X1), np.array([[0, 0], [1, 1]]))
+    assert_array_equal(eclf2.transform(X1), np.array([[0], [1]]))
+
+
+def test_estimator_weights_format(global_random_seed):
+    # Test estimator weights inputs as list and array
+    clf1 = LogisticRegression(random_state=global_random_seed)
+    clf2 = RandomForestClassifier(n_estimators=10, random_state=global_random_seed)
+    eclf1 = VotingClassifier(
+        estimators=[("lr", clf1), ("rf", clf2)], weights=[1, 2], voting="soft"
+    )
+    eclf2 = VotingClassifier(
+        estimators=[("lr", clf1), ("rf", clf2)], weights=np.array((1, 2)), voting="soft"
+    )
+    eclf1.fit(X_scaled, y)
+    eclf2.fit(X_scaled, y)
+    assert_array_almost_equal(
+        eclf1.predict_proba(X_scaled), eclf2.predict_proba(X_scaled)
+    )
+
+
+def test_transform(global_random_seed):
+    """Check transform method of VotingClassifier on toy dataset."""
+    clf1 = LogisticRegression(random_state=global_random_seed)
+    clf2 = RandomForestClassifier(n_estimators=10, random_state=global_random_seed)
+    clf3 = GaussianNB()
+    X = np.array([[-1.1, -1.5], [-1.2, -1.4], [-3.4, -2.2], [1.1, 1.2]])
+    y = np.array([1, 1, 2, 2])
+
+    eclf1 = VotingClassifier(
+        estimators=[("lr", clf1), ("rf", clf2), ("gnb", clf3)], voting="soft"
+    ).fit(X, y)
+    eclf2 = VotingClassifier(
+        estimators=[("lr", clf1), ("rf", clf2), ("gnb", clf3)],
+        voting="soft",
+        flatten_transform=True,
+    ).fit(X, y)
+    eclf3 = VotingClassifier(
+        estimators=[("lr", clf1), ("rf", clf2), ("gnb", clf3)],
+        voting="soft",
+        flatten_transform=False,
+    ).fit(X, y)
+
+    assert_array_equal(eclf1.transform(X).shape, (4, 6))
+    assert_array_equal(eclf2.transform(X).shape, (4, 6))
+    assert_array_equal(eclf3.transform(X).shape, (3, 4, 2))
+    assert_array_almost_equal(eclf1.transform(X), eclf2.transform(X))
+    assert_array_almost_equal(
+        eclf3.transform(X).swapaxes(0, 1).reshape((4, 6)), eclf2.transform(X)
+    )
+
+
+@pytest.mark.parametrize(
+    "X, y, voter",
+    [
+        (
+            X,
+            y,
+            VotingClassifier(
+                [
+                    ("lr", LogisticRegression()),
+                    ("rf", RandomForestClassifier(n_estimators=5)),
+                ]
+            ),
+        ),
+        (
+            X_r,
+            y_r,
+            VotingRegressor(
+                [
+                    ("lr", LinearRegression()),
+                    ("rf", RandomForestRegressor(n_estimators=5)),
+                ]
+            ),
+        ),
+    ],
+)
+def test_none_estimator_with_weights(X, y, voter):
+    # check that an estimator can be set to 'drop' and passing some weight
+    # regression test for
+    # https://github.com/scikit-learn/scikit-learn/issues/13777
+    voter = clone(voter)
+    # Scaled to solve ConvergenceWarning throw by Logistic Regression
+    X_scaled = StandardScaler().fit_transform(X)
+    voter.fit(X_scaled, y, sample_weight=np.ones(y.shape))
+    voter.set_params(lr="drop")
+    voter.fit(X_scaled, y, sample_weight=np.ones(y.shape))
+    y_pred = voter.predict(X_scaled)
+    assert y_pred.shape == y.shape
+
+
+@pytest.mark.parametrize(
+    "est",
+    [
+        VotingRegressor(
+            estimators=[
+                ("lr", LinearRegression()),
+                ("tree", DecisionTreeRegressor(random_state=0)),
+            ]
+        ),
+        VotingClassifier(
+            estimators=[
+                ("lr", LogisticRegression(random_state=0)),
+                ("tree", DecisionTreeClassifier(random_state=0)),
+            ]
+        ),
+    ],
+    ids=["VotingRegressor", "VotingClassifier"],
+)
+def test_n_features_in(est):
+    est = clone(est)
+    X = [[1, 2], [3, 4], [5, 6]]
+    y = [0, 1, 2]
+
+    assert not hasattr(est, "n_features_in_")
+    est.fit(X, y)
+    assert est.n_features_in_ == 2
+
+
+@pytest.mark.parametrize(
+    "estimator",
+    [
+        VotingRegressor(
+            estimators=[
+                ("lr", LinearRegression()),
+                ("rf", RandomForestRegressor(random_state=123)),
+            ],
+            verbose=True,
+        ),
+        VotingClassifier(
+            estimators=[
+                ("lr", LogisticRegression(random_state=123)),
+                ("rf", RandomForestClassifier(random_state=123)),
+            ],
+            verbose=True,
+        ),
+    ],
+)
+def test_voting_verbose(estimator, capsys):
+    X = np.array([[-1.1, -1.5], [-1.2, -1.4], [-3.4, -2.2], [1.1, 1.2]])
+    y = np.array([1, 1, 2, 2])
+
+    pattern = (
+        r"\[Voting\].*\(1 of 2\) Processing lr, total=.*\n"
+        r"\[Voting\].*\(2 of 2\) Processing rf, total=.*\n$"
+    )
+    clone(estimator).fit(X, y)
+    assert re.match(pattern, capsys.readouterr()[0])
+
+
+def test_get_features_names_out_regressor():
+    """Check get_feature_names_out output for regressor."""
+
+    X = [[1, 2], [3, 4], [5, 6]]
+    y = [0, 1, 2]
+
+    voting = VotingRegressor(
+        estimators=[
+            ("lr", LinearRegression()),
+            ("tree", DecisionTreeRegressor(random_state=0)),
+            ("ignore", "drop"),
+        ]
+    )
+    voting.fit(X, y)
+
+    names_out = voting.get_feature_names_out()
+    expected_names = ["votingregressor_lr", "votingregressor_tree"]
+    assert_array_equal(names_out, expected_names)
+
+
+@pytest.mark.parametrize(
+    "kwargs, expected_names",
+    [
+        (
+            {"voting": "soft", "flatten_transform": True},
+            [
+                "votingclassifier_lr0",
+                "votingclassifier_lr1",
+                "votingclassifier_lr2",
+                "votingclassifier_tree0",
+                "votingclassifier_tree1",
+                "votingclassifier_tree2",
+            ],
+        ),
+        ({"voting": "hard"}, ["votingclassifier_lr", "votingclassifier_tree"]),
+    ],
+)
+def test_get_features_names_out_classifier(kwargs, expected_names):
+    """Check get_feature_names_out for classifier for different settings."""
+    X = [[1, 2], [3, 4], [5, 6], [1, 1.2]]
+    y = [0, 1, 2, 0]
+
+    voting = VotingClassifier(
+        estimators=[
+            ("lr", LogisticRegression(random_state=0)),
+            ("tree", DecisionTreeClassifier(random_state=0)),
+        ],
+        **kwargs,
+    )
+    voting.fit(X, y)
+    X_trans = voting.transform(X)
+    names_out = voting.get_feature_names_out()
+
+    assert X_trans.shape[1] == len(expected_names)
+    assert_array_equal(names_out, expected_names)
+
+
+def test_get_features_names_out_classifier_error():
+    """Check that error is raised when voting="soft" and flatten_transform=False."""
+    X = [[1, 2], [3, 4], [5, 6]]
+    y = [0, 1, 2]
+
+    voting = VotingClassifier(
+        estimators=[
+            ("lr", LogisticRegression(random_state=0)),
+            ("tree", DecisionTreeClassifier(random_state=0)),
+        ],
+        voting="soft",
+        flatten_transform=False,
+    )
+    voting.fit(X, y)
+
+    msg = (
+        "get_feature_names_out is not supported when `voting='soft'` and "
+        "`flatten_transform=False`"
+    )
+    with pytest.raises(ValueError, match=msg):
+        voting.get_feature_names_out()
+
+
+# Metadata Routing Tests
+# ======================
+
+
+@pytest.mark.parametrize(
+    "Estimator, Child",
+    [(VotingClassifier, ConsumingClassifier), (VotingRegressor, ConsumingRegressor)],
+)
+def test_routing_passed_metadata_not_supported(Estimator, Child):
+    """Test that the right error message is raised when metadata is passed while
+    not supported when `enable_metadata_routing=False`."""
+
+    X = np.array([[0, 1], [2, 2], [4, 6]])
+    y = [1, 2, 3]
+
+    with pytest.raises(
+        ValueError, match="is only supported if enable_metadata_routing=True"
+    ):
+        Estimator(["clf", Child()]).fit(X, y, sample_weight=[1, 1, 1], metadata="a")
+
+
+@pytest.mark.parametrize(
+    "Estimator, Child",
+    [(VotingClassifier, ConsumingClassifier), (VotingRegressor, ConsumingRegressor)],
+)
+@config_context(enable_metadata_routing=True)
+def test_get_metadata_routing_without_fit(Estimator, Child):
+    # Test that metadata_routing() doesn't raise when called before fit.
+    est = Estimator([("sub_est", Child())])
+    est.get_metadata_routing()
+
+
+@pytest.mark.parametrize(
+    "Estimator, Child",
+    [(VotingClassifier, ConsumingClassifier), (VotingRegressor, ConsumingRegressor)],
+)
+@pytest.mark.parametrize("prop", ["sample_weight", "metadata"])
+@config_context(enable_metadata_routing=True)
+def test_metadata_routing_for_voting_estimators(Estimator, Child, prop):
+    """Test that metadata is routed correctly for Voting*."""
+    X = np.array([[0, 1], [2, 2], [4, 6]])
+    y = [1, 2, 3]
+    sample_weight, metadata = [1, 1, 1], "a"
+
+    est = Estimator(
+        [
+            (
+                "sub_est1",
+                Child(registry=_Registry()).set_fit_request(**{prop: True}),
+            ),
+            (
+                "sub_est2",
+                Child(registry=_Registry()).set_fit_request(**{prop: True}),
+            ),
+        ]
+    )
+
+    est.fit(X, y, **{prop: sample_weight if prop == "sample_weight" else metadata})
+
+    for estimator in est.estimators:
+        if prop == "sample_weight":
+            kwargs = {prop: sample_weight}
+        else:
+            kwargs = {prop: metadata}
+        # access sub-estimator in (name, est) with estimator[1]
+        registry = estimator[1].registry
+        assert len(registry)
+        for sub_est in registry:
+            check_recorded_metadata(obj=sub_est, method="fit", parent="fit", **kwargs)
+
+
+@pytest.mark.parametrize(
+    "Estimator, Child",
+    [(VotingClassifier, ConsumingClassifier), (VotingRegressor, ConsumingRegressor)],
+)
+@config_context(enable_metadata_routing=True)
+def test_metadata_routing_error_for_voting_estimators(Estimator, Child):
+    """Test that the right error is raised when metadata is not requested."""
+    X = np.array([[0, 1], [2, 2], [4, 6]])
+    y = [1, 2, 3]
+    sample_weight, metadata = [1, 1, 1], "a"
+
+    est = Estimator([("sub_est", Child())])
+
+    error_message = (
+        "[sample_weight, metadata] are passed but are not explicitly set as requested"
+        f" or not requested for {Child.__name__}.fit"
+    )
+
+    with pytest.raises(ValueError, match=re.escape(error_message)):
+        est.fit(X, y, sample_weight=sample_weight, metadata=metadata)
+
+
+# End of Metadata Routing Tests
+# =============================