1 files changed, 6 insertions, 0 deletions
diff --git a/Lib/test/test_keywordonlyarg.py b/Lib/test/test_keywordonlyarg.py
index 61d40f9..0503a7f 100644
--- a/Lib/test/test_keywordonlyarg.py
+++ b/Lib/test/test_keywordonlyarg.py
@@ -170,6 +170,12 @@ class KeywordOnlyArgTestCase(unittest.TestCase):
         # used to fail with a SystemError.
         lambda *, k1=unittest: None
 
+    def test_mangling(self):
+        class X:
+            def f(self, *, __a=42):
+                return __a
+        self.assertEqual(X().f(), 42)
+
 def test_main():
     run_unittest(KeywordOnlyArgTestCase)