1 files changed, 5 insertions, 0 deletions
diff --git a/Lib/test/test_weakset.py b/Lib/test/test_weakset.py
index 569facd..49a9b5c 100644
--- a/Lib/test/test_weakset.py
+++ b/Lib/test/test_weakset.py
@@ -2,6 +2,7 @@ import unittest
 from weakref import WeakSet
 import string
 from collections import UserString as ustr
+from collections.abc import Set, MutableSet
 import gc
 import contextlib
 
@@ -437,6 +438,10 @@ class TestWeakSet(unittest.TestCase):
     def test_repr(self):
         assert repr(self.s) == repr(self.s.data)
 
+    def test_abc(self):
+        self.assertIsInstance(self.s, Set)
+        self.assertIsInstance(self.s, MutableSet)
+
 
 if __name__ == "__main__":
     unittest.main()