diff --git a/test/fiber/t_fib1.ml b/test/fiber/t_fib1.ml
index 9235fcf5..1f4207b4 100644
--- a/test/fiber/t_fib1.ml
+++ b/test/fiber/t_fib1.ml
@@ -80,10 +80,10 @@ let () =
          let clock = ref (0 :: i :: clock0) in
          logf !clock "await fiber %d" i;
          logf (TS.tick_get clock) "cur fiber[%d] is some: %b" i
-           (Option.is_some @@ F.Private_.get_cur ());
+           (Option.is_some @@ F.Private_.get_cur_opt ());
          let res = F.await f in
          logf (TS.tick_get clock) "cur fiber[%d] is some: %b" i
-           (Option.is_some @@ F.Private_.get_cur ());
+           (Option.is_some @@ F.Private_.get_cur_opt ());
          F.yield ();
          logf (TS.tick_get clock) "res %d = %d" i res)
        subs);
diff --git a/test/fiber/t_fls.ml b/test/fiber/t_fls.ml
index 01ee96ef..be6deab1 100644
--- a/test/fiber/t_fls.ml
+++ b/test/fiber/t_fls.ml
@@ -7,7 +7,7 @@ module FLS = Moonpool_fib.Fls
 
 type span_id = int
 
-let k_parent : span_id option FLS.key = FLS.new_key ~init:(fun () -> None) ()
+let k_parent : span_id option FLS.t = FLS.create ()
 let ( let@ ) = ( @@ )
 let spf = Printf.sprintf
 
@@ -39,7 +39,7 @@ module Tracer = struct
 
   let with_span self name f =
     let id = Span.new_id_ () in
-    let parent = FLS.get k_parent in
+    let parent = FLS.get ~default:None k_parent in
     let span = { Span.id; parent; msg = name } in
     add self span;
     FLS.with_value k_parent (Some id) f