diff --git a/src/cbor/tests/dune b/src/cbor/tests/dune
index 7ae1aeb4..a596ddc2 100644
--- a/src/cbor/tests/dune
+++ b/src/cbor/tests/dune
@@ -11,16 +11,3 @@
  (deps t_appendix_a.exe appendix_a.json)
  (action
   (run ./t_appendix_a.exe ./appendix_a.json)))
-
-(executable
- (name t)
- (modules t)
- (preprocess
-  (action
-   (run %{project_root}/src/core/cpp/cpp.exe %{input-file})))
- (libraries qcheck-core qcheck-core.runner containers containers.cbor))
-
-(rule
- (alias runtest)
- (action
-  (run ./t.exe --no-colors)))
diff --git a/tests/core/dune b/tests/core/dune
index 8a91091f..605daf0c 100644
--- a/tests/core/dune
+++ b/tests/core/dune
@@ -5,5 +5,5 @@
  (preprocess
   (action
    (run %{project_root}/src/core/cpp/cpp.exe %{input-file})))
- (libraries containers containers.bencode containers.unix threads
-   containers_testlib iter gen uutf csexp))
+ (libraries containers containers.bencode containers.cbor containers.unix
+   threads containers_testlib iter gen uutf csexp))
diff --git a/tests/core/t.ml b/tests/core/t.ml
index f3c74c44..a4f5944a 100644
--- a/tests/core/t.ml
+++ b/tests/core/t.ml
@@ -33,5 +33,6 @@ Containers_testlib.run_all ~descr:"containers" [
   T_utf8string.get();
   T_vector.get();
   T_bencode.get();
+  T_cbor.get();
   T_unix.get();
 ];;
diff --git a/src/cbor/tests/t.ml b/tests/core/t_cbor.ml
similarity index 75%
rename from src/cbor/tests/t.ml
rename to tests/core/t_cbor.ml
index 0199b53d..c358ee1d 100644
--- a/src/cbor/tests/t.ml
+++ b/tests/core/t_cbor.ml
@@ -1,10 +1,8 @@
 
-module Q = QCheck
-module Cbor = Containers_cbor
+include (val Containers_testlib.make ~__FILE__ ())
+module Cbor = Containers_cbor;;
 
-let suite = ref []
-
-[@@@ifge 4.08]
+[@@@ifge 4.08];;
 
 let gen_c : Cbor.t Q.Gen.t =
   let open Q.Gen in
@@ -55,20 +53,14 @@ let rec shrink (c:Cbor.t) : Cbor.t Q.Iter.t =
   | `Bytes s ->
     let+ s = Q.Shrink.string s in `Bytes s
 
+let arb = Q.make ~shrink ~print:Cbor.to_string_diagnostic gen_c;;
 
-let arb = Q.make ~shrink ~print:Cbor.to_string_diagnostic gen_c
-
-let t1 =
-  Q.Test.make ~count:10_000 ~name:"to_from_same" arb @@ fun c ->
-    let s = Cbor.encode c in
-    let c' = Cbor.decode_exn s in
-    if not (c = c') then
-      Q.Test.fail_reportf "@[<hv2>roundtrip failed:@ from %a@ to %a@]"
-      Cbor.pp_diagnostic c Cbor.pp_diagnostic c';
-    true
-
-let () = suite := t1 :: !suite
+q ~count:10_000 arb @@ fun c ->
+  let s = Cbor.encode c in
+  let c' = Cbor.decode_exn s in
+  if not (c = c') then
+    Q.Test.fail_reportf "@[<hv2>roundtrip failed:@ from %a@ to %a@]"
+    Cbor.pp_diagnostic c Cbor.pp_diagnostic c';
+  true;;
 
 [@@@endif]
-
-let () = QCheck_base_runner.run_tests_main !suite