`typing.NoDefault` is not tested to be final

[sobolevn]

Currently NoDefaultTests cover many major use-cases:

cpython/Lib/test/test_typing.py

Lines 11096 to 11132 in 426f99c

	class NoDefaultTests(BaseTestCase):
	def test_pickling(self):
	for proto in range(pickle.HIGHEST_PROTOCOL + 1):
	s = pickle.dumps(NoDefault, proto)
	loaded = pickle.loads(s)
	self.assertIs(NoDefault, loaded)
	def test_constructor(self):
	self.assertIs(NoDefault, type(NoDefault)())
	with self.assertRaises(TypeError):
	type(NoDefault)(1)
	def test_repr(self):
	self.assertEqual(repr(NoDefault), 'typing.NoDefault')
	@requires_docstrings
	def test_doc(self):
	self.assertIsInstance(NoDefault.__doc__, str)
	def test_class(self):
	self.assertIs(NoDefault.__class__, type(NoDefault))
	def test_no_call(self):
	with self.assertRaises(TypeError):
	NoDefault()
	def test_no_attributes(self):
	with self.assertRaises(AttributeError):
	NoDefault.foo = 3
	with self.assertRaises(AttributeError):
	NoDefault.foo
	# TypeError is consistent with the behavior of NoneType
	with self.assertRaises(TypeError):
	type(NoDefault).foo = 3
	with self.assertRaises(AttributeError):
	type(NoDefault).foo

However, they never test that NoDefault type is final, since it does not have Py_TPFLAGS_BASETYPE flag set.

I will send a PR.

Linked PRs

• gh-149410: Test that typing.NoDefault is final #149411
• [3.14] gh-149410: Test that typing.NoDefault is final (GH-149411) #149419
• [3.13] gh-149410: Test that typing.NoDefault is final (GH-149411) #149420