diff --git a/t/function.t b/t/function.t
index 6676659..8fcb1bf 100644
--- a/t/function.t
+++ b/t/function.t
@@ -1,4 +1,4 @@
-(plan 5)
+(plan 6)
 
 (defun inc (a) (+ a 1))
 
@@ -18,3 +18,6 @@
           (equal a 'top))
   (expect "parameters shadow outer bindings"
           (equal (test 'param) 'param)))
+
+(expect "inc"
+        (equal (apply + '(7 5)) 12))