diff --git a/containers.opam b/containers.opam
index 14002208..e9d50fae 100644
--- a/containers.opam
+++ b/containers.opam
@@ -20,6 +20,7 @@ depends: [
   "ounit" { with-test }
   "iter" { with-test }
   "gen" { with-test }
+  "csexp" { with-test }
   "uutf" { with-test }
   "odoc" { with-doc }
 ]
diff --git a/src/core/tests/dune b/src/core/tests/dune
index ef6300eb..03ca9a0d 100644
--- a/src/core/tests/dune
+++ b/src/core/tests/dune
@@ -18,15 +18,27 @@
   (modules test_random)
   (libraries containers))
 
+(executable
+  (name test_csexp)
+  (flags :standard -warn-error -a+8)
+  (modules test_csexp)
+  (libraries containers csexp qcheck-core qcheck))
+
 (alias
   (name runtest)
-  (locks ctest)
+  (locks /ctest)
   (package containers)
   (action (run ./test_random.exe)))
 
+(alias
+  (name runtest)
+  (locks /ctest)
+  (package containers)
+  (action (run ./test_csexp.exe)))
+
 ; what matters is that it compiles
 (alias
   (name runtest)
-  (locks ctest)
+  (locks /ctest)
   (package containers)
   (action  (run ./check_labelled_mods.exe)))
diff --git a/src/core/tests/test_csexp.ml b/src/core/tests/test_csexp.ml
new file mode 100644
index 00000000..eb66022d
--- /dev/null
+++ b/src/core/tests/test_csexp.ml
@@ -0,0 +1,87 @@
+
+module Q = QCheck
+module CS = CCCanonical_sexp
+
+
+module Csexp_arg = struct
+  open Csexp
+  type t = Csexp.t
+  let atom s = Atom s
+  let list l = List l
+  let match_ s ~atom ~list = match s with
+    | Atom s -> atom s
+    | List l -> list l
+  type loc = unit
+  let make_loc = None
+  let atom_with_loc ~loc:() = atom
+  let list_with_loc ~loc:() = list
+end
+
+module CS0 = CS.Make(Csexp_arg)
+module Sexp0 = CCSexp.Make(Csexp_arg)
+
+let gen_csexp (str:string Q.Gen.t) : CS0.t Q.Gen.t =
+  let open Q.Gen in
+  let open Csexp in
+  begin fix @@ fun self depth ->
+    let mklist n =
+      list_size (0 -- n) (self (depth+1)) >|= fun l -> List l
+    in
+    frequency @@ List.flatten [
+      [(3, str
+        >|= fun s -> Atom s)];
+      (match depth with
+        | 0 -> [4,mklist 25]
+        | 1 -> [2,mklist 7]
+        | 2 -> [1,mklist 2]
+        | _ -> []);
+    ]
+  end 0
+
+let rec shrink_csexp (s:Csexp.t) : Csexp.t Q.Iter.t =
+  let open Csexp in
+  let open Q.Iter in
+  match s with
+    | Atom s -> Q.Shrink.string s >|= fun s -> Atom s
+    | List l -> Q.Shrink.list ~shrink:shrink_csexp l >|= fun l -> List l
+
+let arb_csexp_pp =
+  let genstr = Q.Gen.(string_size ~gen:Q.Gen.printable (0--15)) in
+  Q.make ~print:Sexp0.to_string
+    ~shrink:shrink_csexp (gen_csexp genstr)
+
+let arb_csexp_arb =
+  (* binary-ready *)
+  let genchar = Q.Gen.(0 -- 255 >|=Char.chr) in
+  let genstr = Q.Gen.(string_size ~gen:genchar (0--15)) in
+  Q.make
+    ~print:Sexp0.to_string
+    ~shrink:shrink_csexp (gen_csexp genstr)
+
+module Make(X : sig val arb : Csexp.t Q.arbitrary end) = struct
+  open X
+  let test_print_cc_parse_csexp =
+    Q.Test.make ~count:2_000 ~name:"cc-print-csexp-parse" arb @@ fun sexp ->
+    let s = CS0.to_string sexp in
+    match Csexp.parse_string s with
+      | Ok sexp' -> sexp = sexp'
+      | Error (_,msg) -> Q.Test.fail_report msg
+
+  let test_print_csexp_parse_cc =
+    Q.Test.make ~count:2_000 ~name:"cc-parse-csexp-print" arb @@ fun sexp ->
+    let s = Csexp.to_string sexp in
+    match CS0.parse_string s with
+      | Ok sexp' -> sexp = sexp'
+      | Error msg -> Q.Test.fail_report msg
+
+  let suite = [test_print_cc_parse_csexp; test_print_csexp_parse_cc ]
+end
+
+let suite =
+  let module M1 = Make(struct let arb=arb_csexp_pp end) in
+  let module M2 = Make(struct let arb=arb_csexp_arb end) in
+  List.flatten [M1.suite; M2.suite]
+
+let () =
+  QCheck_base_runner.run_tests_main suite
+