bpo-36949: Implement __repr__ on WeakSet (GH-13415)

Lib/_weakrefset.py

@@ -194,3 +194,6 @@ class WeakSet:
 
     def isdisjoint(self, other):
         return len(self.intersection(other)) == 0
+
+    def __repr__(self):
+        return repr(self.data)

Lib/test/test_weakset.py

@@ -434,6 +434,9 @@ class TestWeakSet(unittest.TestCase):
             self.assertGreaterEqual(n2, 0)
             self.assertLessEqual(n2, n1)
 
+    def test_repr(self):
+        assert repr(self.s) == repr(self.s.data)
+
 
 if __name__ == "__main__":
     unittest.main()

Misc/NEWS.d/next/Library/2019-05-19-06-54-26.bpo-36949.jBlG9F.rst

@@ -0,0 +1 @@
+Implement __repr__ for WeakSet objects.