unikernel/duniverse/dune_/test/expect-tests/dune_stats/dune

@@ -0,0 +1,17 @@
+(library
+ (name dune_stats_tests)
+ (inline_tests
+  (deps
+   (sandbox always)))
+ (libraries
+  dune_stats
+  stdune
+  unix
+  ;; This is because of the (implicit_transitive_deps false)
+  ;; in dune-project
+  ppx_expect.config
+  ppx_expect.config_types
+  base
+  ppx_inline_test.config)
+ (preprocess
+  (pps ppx_expect)))

unikernel/duniverse/dune_/test/expect-tests/dune_stats/dune_stats_tests.ml

@@ -0,0 +1,21 @@
+open Stdune
+
+let%expect_test "fd counting" =
+  let module Fd_count = Dune_stats.Private.Fd_count in
+  let get () =
+    match Fd_count.get () with
+    | This n -> n
+    | Unknown -> failwith "no fd counting available"
+  in
+  let base = get () in
+  let r, w = Unix.pipe () in
+  let log () = printfn "fd count: %d" (get () - base) in
+  log ();
+  [%expect {| fd count: 2 |}];
+  Unix.close r;
+  log ();
+  [%expect {| fd count: 1 |}];
+  Unix.close w;
+  log ();
+  [%expect {| fd count: 0 |}]
+;;