gh-98512: Add more tests for ValuesView (GH-98515)

(cherry picked from commit 29e027c)

Co-authored-by: Nikita Sobolev <mail@sobolevn.me>

Author: miss-islington

Lib/test/test_collections.py

@@ -1594,6 +1594,7 @@ def __len__(self):
         containers = [
             seq,
             ItemsView({1: nan, 2: obj}),
+            KeysView({1: nan, 2: obj}),
             ValuesView({1: nan, 2: obj})
         ]
         for container in containers:
@@ -1857,6 +1858,8 @@ def test_MutableMapping_subclass(self):
         mymap['red'] = 5
         self.assertIsInstance(mymap.keys(), Set)
         self.assertIsInstance(mymap.keys(), KeysView)
+        self.assertIsInstance(mymap.values(), Collection)
+        self.assertIsInstance(mymap.values(), ValuesView)
         self.assertIsInstance(mymap.items(), Set)
         self.assertIsInstance(mymap.items(), ItemsView)
 

Lib/test/test_dictviews.py

@@ -320,6 +320,9 @@ def test_abc_registry(self):
         self.assertIsInstance(d.values(), collections.abc.ValuesView)
         self.assertIsInstance(d.values(), collections.abc.MappingView)
         self.assertIsInstance(d.values(), collections.abc.Sized)
+        self.assertIsInstance(d.values(), collections.abc.Collection)
+        self.assertIsInstance(d.values(), collections.abc.Iterable)
+        self.assertIsInstance(d.values(), collections.abc.Container)
 
         self.assertIsInstance(d.items(), collections.abc.ItemsView)
         self.assertIsInstance(d.items(), collections.abc.MappingView)