diff --git a/functional-tests/run-tests b/functional-tests/run-tests
index 7813480..b0c100e 100755
--- a/functional-tests/run-tests
+++ b/functional-tests/run-tests
@@ -13,6 +13,7 @@
 
 ;;------------------------------------------------
 
+;; Returns #t if the xs list matches prefix
 (define (begins-with prefix xs)
   (cond
     ((null? prefix) #t)