From 7436727942ad86c6a23da446597065b3d9a82c17 Mon Sep 17 00:00:00 2001
From: Simon Cruanes <simon.cruanes.2007@m4x.org>
Date: Fri, 15 Dec 2023 22:36:21 -0500
Subject: [PATCH] test: sanity test for flat_map

---
 tests/core/t_list.ml | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/tests/core/t_list.ml b/tests/core/t_list.ml
index bea8fc3d..8cee6945 100644
--- a/tests/core/t_list.ml
+++ b/tests/core/t_list.ml
@@ -124,6 +124,21 @@ eq
    fold_flat_map (fun acc x -> acc + x, [ pf "%d" x; pf "a%d" x ]) 0 [ 1; 2; 3 ])
 ;;
 
+t @@ fun () ->
+let r = Atomic.make 0 in
+let f x =
+  let n = Atomic.fetch_and_add r 1 in
+  [ n, x ]
+in
+
+let l = CCList.flat_map f [ "a"; "b"; "c" ] in
+assert_equal
+  ~printer:Q.Print.(list @@ pair int string)
+  [ 0, "a"; 1, "b"; 2, "c" ]
+  l;
+true
+;;
+
 q
   Q.(list int)
   (fun l ->