commit 0c5ad5499798aed4cd305d324051986ed4c48c8c
author Curtis Bucher <cpbucher5@gmail.com> Mon Mar 30 09:50:57 2020 -0700
committer GitHub <noreply@github.com> Mon Mar 30 09:50:57 2020 -0700
tree 0b3eed641af3e82e7f4ebaeb514bf0aba0970152
parent 676b105111e2399ed400cd13ab113f9aa891760d

Fix bug in test_collections.py (#19221)

Test in TestChainMap() line 257 did not properly check union behavior.

Lib/test/test_collections.py

diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py
index 47c500b..0207823 100644
--- a/Lib/test/test_collections.py
+++ b/Lib/test/test_collections.py
@@ -253,8 +253,9 @@
         # testing behavior between chainmap and iterable key-value pairs
         with self.assertRaises(TypeError):
             cm3 | pairs
+        tmp = cm3.copy()
         cm3 |= pairs
-        self.assertEqual(cm3.maps, [cm3.maps[0] | dict(pairs), *cm3.maps[1:]])
+        self.assertEqual(cm3.maps, [tmp.maps[0] | dict(pairs), *tmp.maps[1:]])
 
         # testing proper return types for ChainMap and it's subclasses
         class Subclass(ChainMap):