diff --git a/test/fiber/t_fls.ml b/test/fiber/t_fls.ml
index 78901b45..4a3125f5 100644
--- a/test/fiber/t_fls.ml
+++ b/test/fiber/t_fls.ml
@@ -3,6 +3,7 @@ open! Moonpool
 let ( let@ ) = ( @@ )
 
 let () =
+  let@ _ = Moonpool_fib.main in
   (let@ pool = Ws_pool.with_ () in
    T_fibers.Fls.run ~pool ~pool_name:"ws_pool" ());