diff --git a/t/function.t b/t/function.t
new file mode 100644
index 0000000..f223821
--- /dev/null
+++ b/t/function.t
@@ -0,0 +1,4 @@
+(defun inc (a) (+ a 1))
+
+(expect "inc 5 == 6" (eq (inc 5) 6))
+(expect "inc 6 == 7" (eq (inc 6) 7))