diff --git a/src/util-set-list.scm b/src/util-set-list.scm
index 7c78a3f..998f568 100644
--- a/src/util-set-list.scm
+++ b/src/util-set-list.scm
@@ -217,6 +217,12 @@
 		  (lset->list
 		   (list->lset '(1 2 3 1 2))))
 		 3)
+    (test-equal? lset-merge
+		 (lset-count
+		  (lset-merge
+		   (list->lset '(1 2 3 1 2))
+		   (list->lset '(2 3 4 2 3))))
+		 4)
     ))
 
  )