def test_f_classif():
    # Test whether the F test yields meaningful results
    # on a simple simulated classification problem
    X, y = make_classification(n_samples=200, n_features=20,
                               n_informative=3, n_redundant=2,
                               n_repeated=0, n_classes=8,
                               n_clusters_per_class=1, flip_y=0.0,
                               class_sep=10, shuffle=False, random_state=0)

    F, pv = f_classif(X, y)
    F_sparse, pv_sparse = f_classif(sparse.csr_matrix(X), y)
    assert_true((F > 0).all())
    assert_true((pv > 0).all())
    assert_true((pv < 1).all())
    assert_true((pv[:5] < 0.05).all())
    assert_true((pv[5:] > 1.e-4).all())
    assert_array_almost_equal(F_sparse, F)
    assert_array_almost_equal(pv_sparse, pv)
dataset/ETHPy150Open scikit-learn/scikit-learn/sklearn/feature_selection/tests/test_feature_select.py/test_f_classif/original