diff --git a/Lib/test/test_weakset.py b/Lib/test/test_weakset.py
index 35db7a6..3c71f62 100644
--- a/Lib/test/test_weakset.py
+++ b/Lib/test/test_weakset.py
@@ -71,6 +71,11 @@
             x = WeakSet(self.items + self.items2)
             c = C(self.items2)
             self.assertEqual(self.s.union(c), x)
+            del c
+        self.assertEqual(len(u), len(self.items) + len(self.items2))
+        self.items2.pop()
+        gc.collect()
+        self.assertEqual(len(u), len(self.items) + len(self.items2))
 
     def test_or(self):
         i = self.s.union(self.items2)
@@ -78,14 +83,19 @@
         self.assertEqual(self.s | frozenset(self.items2), i)
 
     def test_intersection(self):
-        i = self.s.intersection(self.items2)
+        s = WeakSet(self.letters)
+        i = s.intersection(self.items2)
         for c in self.letters:
-            self.assertEqual(c in i, c in self.d and c in self.items2)
-        self.assertEqual(self.s, WeakSet(self.items))
+            self.assertEqual(c in i, c in self.items2 and c in self.letters)
+        self.assertEqual(s, WeakSet(self.letters))
         self.assertEqual(type(i), WeakSet)
         for C in set, frozenset, dict.fromkeys, list, tuple:
             x = WeakSet([])
-            self.assertEqual(self.s.intersection(C(self.items2)), x)
+            self.assertEqual(i.intersection(C(self.items)), x)
+        self.assertEqual(len(i), len(self.items2))
+        self.items2.pop()
+        gc.collect()
+        self.assertEqual(len(i), len(self.items2))
 
     def test_isdisjoint(self):
         self.assertTrue(self.s.isdisjoint(WeakSet(self.items2)))
@@ -116,6 +126,10 @@
         self.assertEqual(self.s, WeakSet(self.items))
         self.assertEqual(type(i), WeakSet)
         self.assertRaises(TypeError, self.s.symmetric_difference, [[]])
+        self.assertEqual(len(i), len(self.items) + len(self.items2))
+        self.items2.pop()
+        gc.collect()
+        self.assertEqual(len(i), len(self.items) + len(self.items2))
 
     def test_xor(self):
         i = self.s.symmetric_difference(self.items2)