bpo-42195: Ensure consistency of Callable's __args__ in collections.abc and typing (GH-23060)
diff --git a/Lib/test/test_genericalias.py b/Lib/test/test_genericalias.py
index c113e53..5de13fe 100644
--- a/Lib/test/test_genericalias.py
+++ b/Lib/test/test_genericalias.py
@@ -62,7 +62,6 @@ class BaseTest(unittest.TestCase):
Iterable, Iterator,
Reversible,
Container, Collection,
- Callable,
Mailbox, _PartialFile,
ContextVar, Token,
Field,
@@ -307,6 +306,63 @@ def test_no_kwargs(self):
with self.assertRaises(TypeError):
GenericAlias(bad=float)
+ def test_subclassing_types_genericalias(self):
+ class SubClass(GenericAlias): ...
+ alias = SubClass(list, int)
+ class Bad(GenericAlias):
+ def __new__(cls, *args, **kwargs):
+ super().__new__(cls, *args, **kwargs)
+
+ self.assertEqual(alias, list[int])
+ with self.assertRaises(TypeError):
+ Bad(list, int, bad=int)
+
+ def test_abc_callable(self):
+ # A separate test is needed for Callable since it uses a subclass of
+ # GenericAlias.
+ alias = Callable[[int, str], float]
+ with self.subTest("Testing subscription"):
+ self.assertIs(alias.__origin__, Callable)
+ self.assertEqual(alias.__args__, (int, str, float))
+ self.assertEqual(alias.__parameters__, ())
+
+ with self.subTest("Testing instance checks"):
+ self.assertIsInstance(alias, GenericAlias)
+
+ with self.subTest("Testing weakref"):
+ self.assertEqual(ref(alias)(), alias)
+
+ with self.subTest("Testing pickling"):
+ s = pickle.dumps(alias)
+ loaded = pickle.loads(s)
+ self.assertEqual(alias.__origin__, loaded.__origin__)
+ self.assertEqual(alias.__args__, loaded.__args__)
+ self.assertEqual(alias.__parameters__, loaded.__parameters__)
+
+ with self.subTest("Testing TypeVar substitution"):
+ C1 = Callable[[int, T], T]
+ C2 = Callable[[K, T], V]
+ C3 = Callable[..., T]
+ self.assertEqual(C1[str], Callable[[int, str], str])
+ self.assertEqual(C2[int, float, str], Callable[[int, float], str])
+ self.assertEqual(C3[int], Callable[..., int])
+
+ with self.subTest("Testing type erasure"):
+ class C1(Callable):
+ def __call__(self):
+ return None
+ a = C1[[int], T]
+ self.assertIs(a().__class__, C1)
+ self.assertEqual(a().__orig_class__, C1[[int], T])
+
+ # bpo-42195
+ with self.subTest("Testing collections.abc.Callable's consistency "
+ "with typing.Callable"):
+ c1 = typing.Callable[[int, str], dict]
+ c2 = Callable[[int, str], dict]
+ self.assertEqual(c1.__args__, c2.__args__)
+ self.assertEqual(hash(c1.__args__), hash(c2.__args__))
+
if __name__ == "__main__":
unittest.main()