added tests for popular use case of PolynomialFeatures min_degree feature

Rumplestomp · Rumplestomp · commit 4b2b012ad91c · 2021-03-21T18:28:09.000-04:00
diff --git a/sklearn/preprocessing/tests/test_data.py b/sklearn/preprocessing/tests/test_data.py
@@ -156,6 +156,18 @@ def test_polynomial_features_max_degree_instead_of_degree():
     res = poly.fit_transform(X)
     assert_array_almost_equal(res, [[1., 2., 3., 4., 6., 8., 12.]])
 
+def test_polynomial_features_min_degree_2_max_degree_bigger():
+    X = [[2, 3, 4]]
+    poly = PolynomialFeatures(max_degree=3, min_degree=2, interaction_only=True)
+    res = poly.fit_transform(X)
+    assert_array_almost_equal(res, [[1., 2., 3., 4., 6., 8., 12., 24.]])
+def test_polynomial_features_min_degree_2_max_degree_bigger_all_combinations():
+    X = [[2, 3, 4]]
+    poly = PolynomialFeatures(max_degree=3, min_degree=2, interaction_only=False)
+    res = poly.fit_transform(X)
+    assert_array_almost_equal(res, [[ 4.,  6.,  8.,  9., 12., 16.,  8., 12., 16., 18., 24., 32., 27.,
+        36., 48., 64.]])
+
 def test_polynomial_feature_names():
     X = np.arange(30).reshape(10, 3)
     poly = PolynomialFeatures(degree=2, include_bias=True).fit(X)
