pythongh-58211: Add test to builtin constants bound method

Author: adorilson

Lib/test/test_funcattrs.py

@@ -504,6 +504,20 @@ def test_builtin__self__(self):
         d = {'foo': 'bar'}
         self.assertEqual(d.pop.__self__, d)
 
+        # builtin constants bound method:
+        self.assertFalse(False.__repr__.__self__)
+        self.assertIsNone(None.__repr__.__self__)
+        self.assertTrue(True.__repr__.__self__)
+
+        ni = NotImplemented
+        self.assertIs(ni.__repr__.__self__, ni)
+
+        e = Ellipsis
+        self.assertIs(e.__repr__.__self__, e)
+
+        d = __debug__
+        self.assertIs(d.__repr__.__self__, d)
+
 
 if __name__ == "__main__":
     unittest.main()