tests added + some bugs fixed

hiclass/Explainer.py

@@ -128,7 +128,7 @@ def _explain_lcpn(self, X):
                 local_explainer = self.explainers[node]
 
         # Calculate SHAP values for the given sample X
-            shap_values = local_explainer.shap_values(X)
+            shap_values = np.array(local_explainer.shap_values(X))
             shap_values_dict[node] = shap_values
 
         return shap_values_dict

tests/test_LocalClassifierPerNode.py

@@ -227,3 +227,63 @@ def test_explainer_not_empty():
     explainer = Explainer(lcpn, data=X, mode="tree")
     shap_dict = explainer.explain(X_test)
     assert shap_dict is not None
+
+
+@pytest.fixture
+def explainer_data():
+    #           a
+    #         /    \
+    #       b       c
+    #      /  \     / \
+    #    d     e   f   g
+    x_train = np.random.randn(4, 3)
+    y_train = np.array(
+        [["a", "b", "d"], ["a", "b", "e"], ["a", "c", "f"], ["a", "c", "g"]]
+    )
+    x_test = np.random.randn(5, 3)
+
+    return x_train, x_test, y_train
+
+
+def test_explainer_tree(explainer_data):
+    rfc = RandomForestClassifier()
+    lcpn = LocalClassifierPerNode(
+        local_classifier=rfc,
+    )
+
+    x_train, x_test, y_train = explainer_data
+    print(explainer_data)
+
+    lcpn.fit(x_train, y_train)
+
+    lcpn.predict(x_test)
+    explainer = Explainer(lcpn, data=x_train, mode="tree")
+    shap_dict = explainer.explain(x_test)
+
+    for key, val in shap_dict.items():
+        # Assert on shapes of shap values, must match (target_classes, num_samples, num_features)
+        model = lcpn.hierarchy_.nodes[key]["classifier"]
+        assert shap_dict[key].shape == (
+            len(model.classes_),
+            x_test.shape[0],
+            x_test.shape[1],
+        )
+
+
+def test_explainer_linear(explainer_data):
+    logreg = LogisticRegression()
+    lcpn = LocalClassifierPerNode(
+        local_classifier=logreg,
+    )
+
+    x_train, x_test, y_train = explainer_data
+    lcpn.fit(x_train, y_train)
+
+    lcpn.predict(x_test)
+    explainer = Explainer(lcpn, data=x_train, mode="linear")
+    shap_dict = explainer.explain(x_test)
+
+    for key, val in shap_dict.items():
+        # Assert on shapes of shap values, must match (num_samples, num_features) Note: Logistic regression is based
+        # on sigmoid and not softmax, hence there are no separate predictions for each target class
+        assert shap_dict[key].shape == x_test.shape