diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py
index e667efb..de9bba1 100644
--- a/Lib/test/test_descr.py
+++ b/Lib/test/test_descr.py
@@ -1751,6 +1751,7 @@
     # Check that negative clones don't segfault
     a = longclone(-1)
     vereq(a.__dict__, {})
+    vereq(long(a), -1)  # verify PyNumber_Long() copies the sign bit
 
     class precfloat(float):
         __slots__ = ['prec']