Add test for __fields__ being read-only
diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py
index 348919f..04d4d9d 100644
--- a/Lib/test/test_collections.py
+++ b/Lib/test/test_collections.py
@@ -43,6 +43,14 @@
self.assertEqual(p.__replace__('x', 1), (1, 22)) # test __replace__ method
self.assertEqual(p.__asdict__(), dict(x=11, y=22)) # test __dict__ method
+ # Verify that __fields__ is read-only
+ try:
+ p.__fields__ = ('F1' ,'F2')
+ except AttributeError:
+ pass
+ else:
+ self.fail('The __fields__ attribute needs to be read-only')
+
# verify that field string can have commas
Point = namedtuple('Point', 'x, y')
p = Point(x=11, y=22)