diff --git a/unittests/list_push_back.chai b/unittests/list_push_back.chai
index 5a058fc..35b8fa6 100644
--- a/unittests/list_push_back.chai
+++ b/unittests/list_push_back.chai
@@ -8,7 +8,5 @@ assert_equal(3, x.front());
 assert_equal("A", x.back());
 
 
-// push_back newly constructed return value that's non-copyable
-x.push_back(async(fun(){}))