bpo-45280: Add test for empty NamedTuple in test_typing (GH-28559)

Co-authored-by: Dong-hee Na <[email protected]>

Author: sobolevn

Lib/test/test_typing.py

@@ -4115,6 +4115,19 @@ def test_namedtuple_special_keyword_names(self):
         self.assertEqual(a.typename, 'foo')
         self.assertEqual(a.fields, [('bar', tuple)])
 
+    def test_empty_namedtuple(self):
+        NT = NamedTuple('NT')
+
+        class CNT(NamedTuple):
+            pass  # empty body
+
+        for struct in [NT, CNT]:
+            with self.subTest(struct=struct):
+                self.assertEqual(struct._fields, ())
+                self.assertEqual(struct._field_defaults, {})
+                self.assertEqual(struct.__annotations__, {})
+                self.assertIsInstance(struct(), struct)
+
     def test_namedtuple_errors(self):
         with self.assertRaises(TypeError):
             NamedTuple.__new__()

Misc/NEWS.d/next/Tests/2021-09-25-11-05-31.bpo-45280.3MA6lC.rst

@@ -0,0 +1 @@
+Add a test case for empty :class:`typing.NamedTuple`.