Update test/test_weakset.py from CPython 3.11.2

Lib/test/test_weakset.py

@@ -1,5 +1,6 @@
 import unittest
 from weakref import WeakSet
+import copy
 import string
 from collections import UserString as ustr
 from collections.abc import Set, MutableSet
@@ -15,6 +16,12 @@ class RefCycle:
     def __init__(self):
         self.cycle = self
 
+class WeakSetSubclass(WeakSet):
+    pass
+
+class WeakSetWithSlots(WeakSet):
+    __slots__ = ('x', 'y')
+
 
 class TestWeakSet(unittest.TestCase):
 
@@ -455,6 +462,30 @@ class TestWeakSet(unittest.TestCase):
         self.assertIsInstance(self.s, Set)
         self.assertIsInstance(self.s, MutableSet)
 
+    def test_copying(self):
+        for cls in WeakSet, WeakSetWithSlots:
+            s = cls(self.items)
+            s.x = ['x']
+            s.z = ['z']
+
+            dup = copy.copy(s)
+            self.assertIsInstance(dup, cls)
+            self.assertEqual(dup, s)
+            self.assertIsNot(dup, s)
+            self.assertIs(dup.x, s.x)
+            self.assertIs(dup.z, s.z)
+            self.assertFalse(hasattr(dup, 'y'))
+
+            dup = copy.deepcopy(s)
+            self.assertIsInstance(dup, cls)
+            self.assertEqual(dup, s)
+            self.assertIsNot(dup, s)
+            self.assertEqual(dup.x, s.x)
+            self.assertIsNot(dup.x, s.x)
+            self.assertEqual(dup.z, s.z)
+            self.assertIsNot(dup.z, s.z)
+            self.assertFalse(hasattr(dup, 'y'))
+
 
 if __name__ == "__main__":
     unittest.main()