diff --git a/src/cbor/tests/dune b/src/cbor/tests/dune
index 5a03065e..529fe539 100644
--- a/src/cbor/tests/dune
+++ b/src/cbor/tests/dune
@@ -1,5 +1,6 @@
 (executable
  (name t_appendix_a)
+ (preprocess (action (run %{project_root}/src/core/cpp/cpp.exe %{input-file})))
  (libraries yojson containers containers.cbor))
 
 (rule
diff --git a/src/cbor/tests/t_appendix_a.ml b/src/cbor/tests/t_appendix_a.ml
index 16958b10..8908d9fb 100644
--- a/src/cbor/tests/t_appendix_a.ml
+++ b/src/cbor/tests/t_appendix_a.ml
@@ -1,3 +1,6 @@
+
+[@@@ifge 4.08]
+
 module J = Yojson.Safe
 module Fmt = CCFormat
 module Cbor = Containers_cbor
@@ -162,3 +165,6 @@ let () =
   (*Format.printf "tests: %a@." (Fmt.Dump.list Test.pp) tests;*)
   run_tests tests;
   ()
+
+
+[@@@endif]