diff --git a/tests/cmdline/cmd_showbc.py b/tests/cmdline/cmd_showbc.py
index 6e99fc4189..916228356f 100644
--- a/tests/cmdline/cmd_showbc.py
+++ b/tests/cmdline/cmd_showbc.py
@@ -108,7 +108,7 @@ def f():
     # closed over variables
     x = 1
     def closure():
-        a = x + 1
+        nonlocal x; a = x + 1
         x = 1
         del x