Fix implementation dependent assertion in test_plistlib. (#4813)

It is failed with an advanced optimizer.

diff --git a/Lib/test/test_plistlib.py b/Lib/test/test_plistlib.py
index ae8b6239690d3220db06ce07af02d820ce52b949..8d8e0a750a224bba9209e4e4d07b419d0494bf34 100644 (file)
--- a/Lib/test/test_plistlib.py
+++ b/Lib/test/test_plistlib.py
@@ -320,7 +320,8 @@ class TestPlistlib(unittest.TestCase):
                     'second': [1, 2],
                     'third': [3, 4],
                 })
-                self.assertIsNot(pl2['first'], pl2['second'])
+                if fmt != plistlib.FMT_BINARY:
+                    self.assertIsNot(pl2['first'], pl2['second'])
 
     def test_list_members(self):
         pl = {