Added testcase and argument check

Author: cubewise-gng

TM1py/Services/SubsetService.py

@@ -215,10 +215,12 @@ def get_element_names(
         """
         # backward compatibility for subset_name
         if "subset_name" in kwargs:
-            subset = kwargs["subset_name"]
+            if subset:
+                raise ValueError("Only one parameter 'subset' or 'subset_name' may be provided.")
+            subset = kwargs.pop("subset_name")
 
         if isinstance(subset, str):
-            subset = self.get(subset, dimension_name, hierarchy_name, private=private, **kwargs)
+            subset = self.get(subset, dimension_name, hierarchy_name, private, **kwargs)
         elif not isinstance(subset, Subset):
             raise ValueError(f"subset argument must be of type 'str' or 'Subset', not '{type(subset)}'.")
 

Tests/SubsetService_test.py

@@ -386,6 +386,33 @@ def test_get_element_names_dynamic(self):
 
         self.assertEqual(["USD", "EUR", "JPY", "CNY", "GBP", "NZD", "Dum'my"], element_names)
 
+    def test_get_element_names_arg_combination(self):
+        element_names = self.tm1.subsets.get_element_names(
+            dimension_name=self.dimension_name, hierarchy_name=self.dimension_name, subset=self.subset_name_static,
+            private=False
+        )
+        self.assertEqual(self.static_subset.elements, element_names)
+
+        element_names = self.tm1.subsets.get_element_names(
+            dimension_name=self.dimension_name, hierarchy_name=self.dimension_name, subset=self.static_subset,
+            private=False
+        )
+        self.assertEqual(self.static_subset.elements, element_names)
+
+        element_names = self.tm1.subsets.get_element_names(
+            dimension_name=self.dimension_name, hierarchy_name=self.dimension_name, subset_name=self.subset_name_static,
+            private=False
+        )
+        self.assertEqual(self.static_subset.elements, element_names)
+
+        with self.assertRaisesRegex(ValueError, "Only one parameter 'subset' or 'subset_name' may be provided."):
+            element_names = self.tm1.subsets.get_element_names(
+                dimension_name=self.dimension_name, hierarchy_name=self.dimension_name,
+                subset=self.subset_name_static,
+                subset_name=self.subset_name_static,
+                private=False
+            )
+
     def test_create_subset_with_url_unfriendly_characters_in_name(self):
         subset = Subset(
             subset_name=self.unfriendly_subset_name,