From 77ace92ec1ef111a73146e54bdf10cce8aab401f Mon Sep 17 00:00:00 2001
From: Simon Cruanes <simon.cruanes.2007@m4x.org>
Date: Fri, 9 Jun 2023 23:57:27 -0400
Subject: [PATCH] add tests for futures

---
 test/dune       |   2 +-
 test/t_futs1.ml | 111 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 112 insertions(+), 1 deletion(-)
 create mode 100644 test/t_futs1.ml

diff --git a/test/dune b/test/dune
index 47ff53ce..490da383 100644
--- a/test/dune
+++ b/test/dune
@@ -1,3 +1,3 @@
 (tests
- (names t_fib t_bench1 t_fib_rec)
+ (names t_fib t_bench1 t_fib_rec t_futs1)
  (libraries moonpool))
diff --git a/test/t_futs1.ml b/test/t_futs1.ml
new file mode 100644
index 00000000..5ee8d113
--- /dev/null
+++ b/test/t_futs1.ml
@@ -0,0 +1,111 @@
+open Moonpool
+
+let pool = Pool.create ~min:4 ()
+let pool2 = Pool.create ~min:2 ()
+
+let () =
+  let fut = Fut.return 1 in
+  assert (Fut.peek fut = Some (Ok 1));
+  assert (Fut.is_resolved fut)
+
+let () =
+  let fut = Fut.fail Not_found (Printexc.get_callstack 1) in
+  assert (Fut.peek fut |> Option.get |> Result.is_error)
+
+let () =
+  let fut, prom = Fut.make () in
+  assert (not @@ Fut.is_resolved fut);
+  Fut.fulfill prom (Ok 42);
+  assert (Fut.peek fut = Some (Ok 42));
+  try
+    Fut.fulfill prom (Ok 1);
+    assert false
+  with _ -> ()
+
+let () =
+  let futs = Array.init 10 (fun i -> Fut.spawn ~on:pool (fun () -> i)) in
+  Array.iteri (fun i fut -> assert (Fut.wait_block_exn fut = i)) futs
+
+let () =
+  let fut =
+    Array.init 10 (fun i -> Fut.spawn ~on:pool (fun () -> i)) |> Fut.join_array
+  in
+  assert (Array.init 10 (fun i -> i) = Fut.wait_block_exn fut)
+
+let () =
+  let fut =
+    Array.init 10 (fun i ->
+        Fut.spawn ~on:pool (fun () ->
+            if i < 9 then
+              i
+            else
+              raise Not_found))
+    |> Fut.join_array
+  in
+  (* must fail *)
+  assert (Fut.wait_block fut |> Result.is_error)
+
+let mk_ret_delay ?(on = pool) n x =
+  Fut.spawn ~on (fun () ->
+      Thread.delay n;
+      x)
+
+let () =
+  let f1 = mk_ret_delay 0.01 1 in
+  let f2 = mk_ret_delay 0.01 2 in
+  let fut = Fut.both f1 f2 in
+  assert (Fut.wait_block_exn fut = (1, 2))
+
+let () =
+  let f1 =
+    Fut.spawn ~on:pool (fun () ->
+        Thread.delay 0.01;
+        1)
+  in
+  let f2 =
+    Fut.spawn ~on:pool (fun () ->
+        Thread.delay 0.01;
+        raise Exit)
+  in
+  let fut = Fut.both f1 f2 in
+  assert (Fut.wait_block fut |> Result.is_error)
+
+let () =
+  let f1 =
+    Fut.spawn ~on:pool (fun () ->
+        Thread.delay 0.01;
+        1)
+    |> Fut.map ~on:pool2 ~f:(fun x -> x + 1)
+  and f2 =
+    Fut.spawn ~on:pool (fun () ->
+        Thread.delay 0.01;
+        10)
+    |> Fut.bind ~on:pool2 ~f:(fun x ->
+           Fut.spawn ~on:pool (fun () ->
+               Thread.delay 0.01;
+               x * 2))
+  in
+  let fut = Fut.both f1 f2 in
+  assert (Fut.wait_block fut = Ok (2, 20))
+
+let () =
+  let f1 = mk_ret_delay 0.01 true in
+  let f2 = mk_ret_delay 0.9 false in
+  let fut = Fut.choose f1 f2 in
+  assert (Fut.wait_block fut = Ok (Either.Left true))
+
+let () =
+  let f1 = mk_ret_delay 0.9 "foo" in
+  let f2 = mk_ret_delay 0.01 "bar" in
+  let fut = Fut.choose_same f1 f2 in
+  assert (Fut.wait_block fut = Ok "bar")
+
+let () =
+  let n = Atomic.make 0 in
+  let fut1 =
+    Fut.for_ ~on:pool 100 (fun i -> ignore (Atomic.fetch_and_add n i : int))
+  and fut2 =
+    Fut.for_ ~on:pool 100 (fun i -> ignore (Atomic.fetch_and_add n i : int))
+  in
+  ignore (Fut.wait_block_exn (Fut.join_list [ fut1; fut2 ]) : _ list);
+  assert (Atomic.get n = 99 * 100)