diff --git a/compiler/tests-ocaml/lib-bigarray/bigarrays.ml b/compiler/tests-ocaml/lib-bigarray/bigarrays.ml
index 066f041ebe..dfe8f30b45 100644
--- a/compiler/tests-ocaml/lib-bigarray/bigarrays.ml
+++ b/compiler/tests-ocaml/lib-bigarray/bigarrays.ml
@@ -969,14 +969,20 @@ let tests () =
   testing_function "output_value/input_value";
   let test_structured_io testno value =
     let tmp = Filename.temp_file "bigarray" ".data" in
+prerr_endline "AAA";
     let oc = open_out_bin tmp in
+prerr_endline "BBB";
     output_value oc value;
     close_out oc;
+prerr_endline "CCC";
     let ic = open_in_bin tmp in
+prerr_endline "DDD";
     let value' = input_value ic in
     close_in ic;
     dump_content_hex tmp;
+prerr_endline "EEE";
     Sys.remove tmp;
+prerr_endline "FFF";
     test testno value value' in
   test_structured_io 1 (from_list int8_signed [1;2;3;-4;127;-128]);
   test_structured_io 2 (from_list int16_signed [1;2;3;-4;127;-128]);