(* Title: Tools/quickcheck.ML
Author: Stefan Berghofer, Florian Haftmann, TU Muenchen
Generic counterexample search engine.
*)
signature QUICKCHECK =
sig
val auto: bool Unsynchronized.ref
val auto_time_limit: int Unsynchronized.ref
val test_term: Proof.context -> bool -> string option -> int -> int -> term ->
(string * term) list option
val add_generator: string * (Proof.context -> term -> int -> term list option) -> theory -> theory
val quickcheck: (string * string) list -> int -> Proof.state -> (string * term) list option
end;
structure Quickcheck : QUICKCHECK =
struct
(* preferences *)
val auto = Unsynchronized.ref false;
val auto_time_limit = Unsynchronized.ref 2500;
val _ =
ProofGeneralPgip.add_preference Preferences.category_tracing
(setmp_CRITICAL auto true (fn () =>
Preferences.bool_pref auto
"auto-quickcheck"
"Whether to enable quickcheck automatically.") ());
val _ =
ProofGeneralPgip.add_preference Preferences.category_tracing
(Preferences.nat_pref auto_time_limit
"auto-quickcheck-time-limit"
"Time limit for automatic quickcheck (in milliseconds).");
(* quickcheck configuration -- default parameters, test generators *)
datatype test_params = Test_Params of
{ size: int, iterations: int, default_type: typ option };
fun dest_test_params (Test_Params { size, iterations, default_type }) =
((size, iterations), default_type);
fun make_test_params ((size, iterations), default_type) =
Test_Params { size = size, iterations = iterations, default_type = default_type };
fun map_test_params f (Test_Params { size, iterations, default_type}) =
make_test_params (f ((size, iterations), default_type));
fun merge_test_params (Test_Params { size = size1, iterations = iterations1, default_type = default_type1 },
Test_Params { size = size2, iterations = iterations2, default_type = default_type2 }) =
make_test_params ((Int.max (size1, size2), Int.max (iterations1, iterations2)),
case default_type1 of NONE => default_type2 | _ => default_type1);
structure Data = TheoryDataFun(
type T = (string * (Proof.context -> term -> int -> term list option)) list
* test_params;
val empty = ([], Test_Params { size = 10, iterations = 100, default_type = NONE });
val copy = I;
val extend = I;
fun merge pp ((generators1, params1), (generators2, params2)) =
(AList.merge (op = : string * string -> bool) (K true) (generators1, generators2),
merge_test_params (params1, params2));
)
val add_generator = Data.map o apfst o AList.update (op =);
(* generating tests *)
fun mk_tester_select name ctxt =
case AList.lookup (op =) ((fst o Data.get o ProofContext.theory_of) ctxt) name
of NONE => error ("No such quickcheck generator: " ^ name)
| SOME generator => generator ctxt;
fun mk_testers ctxt t =
(map snd o fst o Data.get o ProofContext.theory_of) ctxt
|> map_filter (fn generator => try (generator ctxt) t);
fun mk_testers_strict ctxt t =
let
val generators = ((map snd o fst o Data.get o ProofContext.theory_of) ctxt)
val testers = map (fn generator => Exn.capture (generator ctxt) t) generators;
in if forall (is_none o Exn.get_result) testers
then [(Exn.release o snd o split_last) testers]
else map_filter Exn.get_result testers
end;
(* testing propositions *)
fun prep_test_term t =
let
val _ = (null (Term.add_tvars t []) andalso null (Term.add_tfrees t [])) orelse
error "Term to be tested contains type variables";
val _ = null (Term.add_vars t []) orelse
error "Term to be tested contains schematic variables";
val frees = Term.add_frees t [];
in (map fst frees, list_abs_free (frees, t)) end
fun test_term ctxt quiet generator_name size i t =
let
val (names, t') = prep_test_term t;
val testers = case generator_name
of NONE => if quiet then mk_testers ctxt t' else mk_testers_strict ctxt t'
| SOME name => [mk_tester_select name ctxt t'];
fun iterate f 0 = NONE
| iterate f j = case f () handle Match => (if quiet then ()
else warning "Exception Match raised during quickcheck"; NONE)
of NONE => iterate f (j - 1) | SOME q => SOME q;
fun with_testers k [] = NONE
| with_testers k (tester :: testers) =
case iterate (fn () => tester (k - 1)) i
of NONE => with_testers k testers
| SOME q => SOME q;
fun with_size k = if k > size then NONE
else (if quiet then () else priority ("Test data size: " ^ string_of_int k);
case with_testers k testers
of NONE => with_size (k + 1) | SOME q => SOME q);
in case with_size 1
of NONE => NONE
| SOME ts => SOME (names ~~ ts)
end;
fun monomorphic_term thy insts default_T =
let
fun subst (T as TFree (v, S)) =
let
val T' = AList.lookup (op =) insts v
|> the_default (the_default T default_T)
in if Sign.of_sort thy (T, S) then T'
else error ("Type " ^ Syntax.string_of_typ_global thy T ^
" to be substituted for variable " ^
Syntax.string_of_typ_global thy T ^ "\ndoes not have sort " ^
Syntax.string_of_sort_global thy S)
end
| subst T = T;
in (map_types o map_atyps) subst end;
fun test_goal quiet generator_name size iterations default_T insts i assms state =
let
val ctxt = Proof.context_of state;
val thy = Proof.theory_of state;
fun strip (Const ("all", _) $ Abs (_, _, t)) = strip t
| strip t = t;
val {goal = st, ...} = Proof.raw_goal state;
val (gi, frees) = Logic.goal_params (prop_of st) i;
val gi' = Logic.list_implies (assms, subst_bounds (frees, strip gi))
|> monomorphic_term thy insts default_T
|> ObjectLogic.atomize_term thy;
in test_term ctxt quiet generator_name size iterations gi' end;
fun pretty_counterex ctxt NONE = Pretty.str "No counterexamples found."
| pretty_counterex ctxt (SOME cex) =
Pretty.chunks (Pretty.str "Counterexample found:\n" ::
map (fn (s, t) =>
Pretty.block [Pretty.str (s ^ " ="), Pretty.brk 1, Syntax.pretty_term ctxt t]) cex);
(* automatic testing *)
val _ = Context.>> (Specification.add_theorem_hook (fn int => fn state =>
let
val ctxt = Proof.context_of state;
val assms = map term_of (Assumption.all_assms_of ctxt);
val Test_Params { size, iterations, default_type } =
(snd o Data.get o Proof.theory_of) state;
fun test () =
let
val res = TimeLimit.timeLimit (Time.fromMilliseconds (!auto_time_limit))
(try (test_goal true NONE size iterations default_type [] 1 assms)) state;
in
case res of
NONE => state
| SOME NONE => state
| SOME cex => Proof.goal_message (fn () => Pretty.chunks [Pretty.str "",
Pretty.mark Markup.hilite (pretty_counterex ctxt cex)]) state
end handle TimeLimit.TimeOut => (warning "Auto quickcheck: timeout."; state);
in
if int andalso !auto andalso not (!Toplevel.quiet)
then test ()
else state
end));
(* Isar commands *)
fun read_nat s = case (Library.read_int o Symbol.explode) s
of (k, []) => if k >= 0 then k
else error ("Not a natural number: " ^ s)
| (_, _ :: _) => error ("Not a natural number: " ^ s);
fun parse_test_param ctxt ("size", arg) =
(apfst o apfst o K) (read_nat arg)
| parse_test_param ctxt ("iterations", arg) =
(apfst o apsnd o K) (read_nat arg)
| parse_test_param ctxt ("default_type", arg) =
(apsnd o K o SOME) (ProofContext.read_typ ctxt arg)
| parse_test_param ctxt (name, _) =
error ("Bad test parameter: " ^ name);
fun parse_test_param_inst ctxt ("generator", arg) =
(apsnd o apfst o K o SOME) arg
| parse_test_param_inst ctxt (name, arg) =
case try (ProofContext.read_typ ctxt) name
of SOME (TFree (v, _)) => (apsnd o apsnd o AList.update (op =))
(v, ProofContext.read_typ ctxt arg)
| _ => (apfst o parse_test_param ctxt) (name, arg);
fun quickcheck_params_cmd args thy =
let
val ctxt = ProofContext.init thy;
val f = fold (parse_test_param ctxt) args;
in
thy
|> (Data.map o apsnd o map_test_params) f
end;
fun quickcheck args i state =
let
val thy = Proof.theory_of state;
val ctxt = Proof.context_of state;
val default_params = (dest_test_params o snd o Data.get) thy;
val f = fold (parse_test_param_inst ctxt) args;
val (((size, iterations), default_type), (generator_name, insts)) =
f (default_params, (NONE, []));
in
test_goal false generator_name size iterations default_type insts i [] state
end;
fun quickcheck_cmd args i state =
quickcheck args i (Toplevel.proof_of state)
|> Pretty.writeln o pretty_counterex (Toplevel.context_of state);
local structure P = OuterParse and K = OuterKeyword in
val parse_arg = P.name --| P.$$$ "=" -- P.name;
val parse_args = P.$$$ "[" |-- P.list1 parse_arg --| P.$$$ "]"
|| Scan.succeed [];
val _ = OuterSyntax.command "quickcheck_params" "set parameters for random testing" K.thy_decl
(parse_args >> (fn args => Toplevel.theory (quickcheck_params_cmd args)));
val _ = OuterSyntax.improper_command "quickcheck" "try to find counterexample for subgoal" K.diag
(parse_args -- Scan.optional P.nat 1
>> (fn (args, i) => Toplevel.no_timing o Toplevel.keep (quickcheck_cmd args i)));
end; (*local*)
end;
val auto_quickcheck = Quickcheck.auto;
val auto_quickcheck_time_limit = Quickcheck.auto_time_limit;