%% -----------------------------------------------------------------------------
  Copyright © 2010 - 2013 Per Andersson
%%
  Erlang UUID is free software : you can redistribute it and/or modify
%% it under the terms of the GNU Lesser General Public License as
  published by the Free Software Foundation , either version 3 of the
%% License, or (at your option) any later version.
%%
  Erlang UUID is distributed in the hope that it will be useful ,
%% but WITHOUT ANY WARRANTY; without even the implied warranty of
%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU Lesser General Public License for more details .
%%
  You should have received a copy of the GNU Lesser General Public
  License along with Erlang UUID .   If not , see
%% </>.
%% -----------------------------------------------------------------------------
  @author Per  <  >
   2010 - 2013 Per Andersson
%% @doc
  Erlang UUID
%%
%% HERE BE UUID TESTS
%% @end
%% -----------------------------------------------------------------------------

-module(uuid_tests).
-author('Per Andersson').

-include_lib("eunit/include/eunit.hrl").

-include("../src/uuid.hrl").


uuid_binary_test() ->
    Uuid = uuid:uuid4(),

    %% UUID v1
    NodeId = uuid:get_node(),
    ?assertMatch(<<_U0:48, ?UUIDv1:4, _U1:12, ?VARIANT10:2, _U2:14,
                   NodeId/binary>>,
                 uuid:uuid1()),

    NilNode = <<0:48>>,
    ClockSeq = <<ClockSeqHi:6, ClockSeqLow:8>> = <<0:14>>,
    ?assertMatch(<<_U0:48, ?UUIDv1:4, _U1:12, ?VARIANT10:2,
                   ClockSeqLow:8, ClockSeqHi:6, NilNode/binary>>,
                 uuid:uuid1(NilNode, ClockSeq)),

    %% UUID v3
    ?assertMatch(<<_U0:48, ?UUIDv3:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid3(dns, "fqdn.example.com")),
    ?assertEqual(uuid:uuid3(dns, "fqdn.example.com"),
                 uuid:uuid3(dns, "fqdn.example.com")),

    ?assertMatch(<<_U0:48, ?UUIDv3:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid3(oid, "2.5.6")),
    ?assertEqual(uuid:uuid3(oid, "2.5.6"), uuid:uuid3(oid, "2.5.6")),

    ?assertMatch(<<_U0:48, ?UUIDv3:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid3(url, "")),
    ?assertEqual(uuid:uuid3(url, ""),
                 uuid:uuid3(url, "")),

    ?assertMatch(<<_U0:48, ?UUIDv3:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid3(x500, "cn=John Doe, o=Acme, Inc., c=US")),
    ?assertEqual(uuid:uuid3(x500, "cn=John Doe, o=Acme, Inc., c=US"),
                 uuid:uuid3(x500, "cn=John Doe, o=Acme, Inc., c=US")),

    ?assertMatch(<<_U0:48, ?UUIDv3:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid3(nil, "my own unique name")),
    ?assertEqual(uuid:uuid3(nil, "my own unique name"),
                 uuid:uuid3(nil, "my own unique name")),

    ?assertMatch(<<_U0:48, ?UUIDv3:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid3(Uuid, "fqdn.example.com")),
    ?assertEqual(uuid:uuid3(Uuid, "fqdn.example.com"),
                 uuid:uuid3(Uuid, "fqdn.example.com")),

    ?assertMatch(<<_U0:48, ?UUIDv3:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid3(uuid:to_string(Uuid), "fqdn.example.com")),
    ?assertEqual(uuid:uuid3(uuid:to_string(Uuid), "fqdn.example.com"),
                 uuid:uuid3(uuid:to_string(Uuid), "fqdn.example.com")),

    %% UUID v4
    ?assertMatch(<<_U0:48, ?UUIDv4:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid4()),

    %% UUID v5
    ?assertMatch(<<_U0:48, ?UUIDv5:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid5(dns, "fqdn.example.com")),
    ?assertEqual(uuid:uuid5(dns, "fqdn.example.com"),
                 uuid:uuid5(dns, "fqdn.example.com")),

    ?assertMatch(<<_U0:48, ?UUIDv5:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid5(oid, "2.5.6")),
    ?assertEqual(uuid:uuid5(oid, "2.5.6"), uuid:uuid5(oid, "2.5.6")),

    ?assertMatch(<<_U0:48, ?UUIDv5:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid5(url, "")),
    ?assertEqual(uuid:uuid5(url, ""),
                 uuid:uuid5(url, "")),

    ?assertMatch(<<_U0:48, ?UUIDv5:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid5(x500, "cn=John Doe, o=Acme, Inc., c=US")),
    ?assertEqual(uuid:uuid5(x500, "cn=John Doe, o=Acme, Inc., c=US"),
                 uuid:uuid5(x500, "cn=John Doe, o=Acme, Inc., c=US")),

    ?assertMatch(<<_U0:48, ?UUIDv5:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid5(nil, "my own unique name")),
    ?assertEqual(uuid:uuid5(nil, "my own unique name"),
                 uuid:uuid5(nil, "my own unique name")),

    ?assertMatch(<<_U0:48, ?UUIDv5:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid5(Uuid, "fqdn.example.com")),
    ?assertEqual(uuid:uuid5(Uuid, "fqdn.example.com"),
                 uuid:uuid5(Uuid, "fqdn.example.com")),

    ?assertMatch(<<_U0:48, ?UUIDv5:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid5(uuid:to_string(Uuid), "fqdn.example.com")),
    ?assertEqual(uuid:uuid5(uuid:to_string(Uuid), "fqdn.example.com"),
                 uuid:uuid5(uuid:to_string(Uuid), "fqdn.example.com")).

representation_test() ->
    Uuid1 = uuid:uuid1(),
    Uuid3 = uuid:uuid5(dns, "fqdn.example.com"),
    Uuid4 = uuid:uuid4(),
    Uuid5 = uuid:uuid5(dns, "fqdn.example.com"),
    ?assertMatch(Uuid1, uuid:to_binary(uuid:to_string(Uuid1))),
    ?assertMatch(Uuid3, uuid:to_binary(uuid:to_string(Uuid3))),
    ?assertMatch(Uuid4, uuid:to_binary(uuid:to_string(Uuid4))),
    ?assertMatch(Uuid5, uuid:to_binary(uuid:to_string(Uuid5))).

conversion_test() ->
    SimpleUuid = "8fd7fa874c205809a1b0e07f5c224f02",
    PrettyUuid = "8fd7fa87-4c20-5809-a1b0-e07f5c224f02",
    ?assertMatch(PrettyUuid,
                 uuid:to_string(uuid:uuid5(dns, "fqdn.example.com"))),
    ?assertMatch(PrettyUuid,
                 uuid:to_string(pretty, uuid:uuid5(dns, "fqdn.example.com"))),
    ?assertMatch(SimpleUuid,
                 uuid:to_string(simple, uuid:uuid5(dns, "fqdn.example.com"))),

    ?assertMatch(PrettyUuid,
                 uuid:to_string(uuid:to_binary(SimpleUuid))),
    ?assertMatch(SimpleUuid,
                 uuid:to_string(simple, uuid:to_binary(SimpleUuid))),
    ?assertMatch(PrettyUuid,
                 uuid:to_string(pretty, uuid:to_binary(PrettyUuid))).

exceptions_test() ->
    ?assertMatch(ok, try_badarg(to_binary, [0])),
    ?assertMatch(ok, try_badarg(to_string, [0])),
    ?assertMatch(ok, try_badarg(to_string, [0, 0])),
    ?assertMatch(ok, try_badarg(uuid3,     [0, 0])),
    ?assertMatch(ok, try_badarg(uuid5,     [0, 0])),
    ?assertMatch(ok, try_badarg(version,   [0])).

urn_test() ->
    UuidBin = uuid:uuid4(),
    UrnBin  = uuid:to_uuid_urn(UuidBin),
    UuidStr = uuid:to_string(UuidBin),
    UrnStr  = uuid:to_uuid_urn(UuidStr),

    [$u,$r,$n,$:,$u,$u,$i,$d,$:|UrnUuidBinStr] = UrnBin,
    ?assertMatch(UrnUuidBinStr, uuid:to_string(UuidBin)),

    [$u,$r,$n,$:,$u,$u,$i,$d,$:|UrnUuidStr] = UrnStr,
    ?assertMatch(UrnUuidStr, UuidStr),

    ?assertMatch(UrnUuidBinStr, UrnUuidStr),

    ?assertMatch(UrnBin, uuid:to_uuid_urn(UrnBin)).

version_test() ->
    Uuid1 = uuid:uuid1(),
    Uuid3 = uuid:uuid3(nil, ""),
    Uuid4 = uuid:uuid4(),
    Uuid5 = uuid:uuid5(nil, ""),

    ?assertMatch(?UUIDv1, uuid:version(Uuid1)),
    ?assertMatch(?UUIDv3, uuid:version(Uuid3)),
    ?assertMatch(?UUIDv4, uuid:version(Uuid4)),
    ?assertMatch(?UUIDv5, uuid:version(Uuid5)),

    Uuids = [Uuid1, Uuid3, Uuid4, Uuid5],

    ?assertMatch([true, false, false, false],
                 lists:map(fun uuid:is_v1/1, Uuids)),

    ?assertMatch([false, true, false, false],
                 lists:map(fun uuid:is_v3/1, Uuids)),

    ?assertMatch([false, false, true, false],
                 lists:map(fun uuid:is_v4/1, Uuids)),

    ?assertMatch([false, false, false, true],
                 lists:map(fun uuid:is_v5/1, Uuids)),

    ?assertMatch([rfc4122, rfc4122, rfc4122, rfc4122],
                 lists:map(fun uuid:variant/1, Uuids)),
    ?assertMatch([true, true, true, true],
                 lists:map(fun uuid:is_valid/1, Uuids)),

    ?assertMatch([reserved_ncs, reserved_microsoft, reserved_future],
                 lists:map(fun uuid:variant/1,
                           [<<0:64, 0:1, 0:1, 0:1, 0:61>>,
                            <<0:64, 1:1, 1:1, 0:1, 0:61>>,
                            <<0:64, 1:1, 1:1, 1:1, 0:61>>])),

    ?assertMatch(false, uuid:is_valid(<<1:128>>)),
    ?assertMatch(true, uuid:is_valid(<<0:128>>)).

stress_test_() ->
    {inparallel,
     {"uuid4 stress test.", {timeout, 10000, uuid4_stress()}}}.

uuid4_stress() ->
    Count = 100000,
    Uuids = [uuid:uuid4() || _ <- lists:seq(1, Count)],
    Uniqs = lists:usort(Uuids),
    ?_assertEqual(Count, length(Uniqs)).

do_randomized_and_timebased_uuids_change_enough_test() ->
    uuid_mask(fun uuid:uuid1/0, "^...XXXXX-....-1...-XXXX-............$"),
    uuid_mask(fun uuid:uuid4/0, "^XXXXXXXX-XXXX-4XXX-XXXX-XXXXXXXXXXXX$").

uuid_mask(F, Mask) ->
    ?assertEqual({match,[{0,36}]},
        re:run(do_uuid_mask(F, 100), Mask)).

do_uuid_mask(F, N) ->
    lists:foldl(fun mask/2,
        uuid:to_string(F()),
        [uuid:to_string(F()) || _ <- lists:seq(1,N)]).

mask(X, Y) -> lists:map(fun eq_or_x/1, lists:zip(X, Y)).

eq_or_x({X, X}) -> X;
eq_or_x(_) -> $X.

%% helper functions
try_badarg(F, A) ->
    try
        apply(uuid, F, A)
    catch error:badarg ->
        ok
    end.

 -----------------------------------------------------------------------------

 it under the terms of the GNU Lesser General Public License as
 License, or (at your option) any later version.

 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 </>.
 -----------------------------------------------------------------------------
 @doc

 HERE BE UUID TESTS
 @end
 -----------------------------------------------------------------------------
 UUID v1
 UUID v3
 UUID v4
 UUID v5
 helper functions
  Copyright © 2010 - 2013 Per Andersson
  Erlang UUID is free software : you can redistribute it and/or modify
  published by the Free Software Foundation , either version 3 of the
  Erlang UUID is distributed in the hope that it will be useful ,
  GNU Lesser General Public License for more details .
  You should have received a copy of the GNU Lesser General Public
  License along with Erlang UUID .   If not , see
  @author Per  <  >
   2010 - 2013 Per Andersson
  Erlang UUID

-module(uuid_tests).
-author('Per Andersson').

-include_lib("eunit/include/eunit.hrl").

-include("../src/uuid.hrl").


uuid_binary_test() ->
    Uuid = uuid:uuid4(),

    NodeId = uuid:get_node(),
    ?assertMatch(<<_U0:48, ?UUIDv1:4, _U1:12, ?VARIANT10:2, _U2:14,
                   NodeId/binary>>,
                 uuid:uuid1()),

    NilNode = <<0:48>>,
    ClockSeq = <<ClockSeqHi:6, ClockSeqLow:8>> = <<0:14>>,
    ?assertMatch(<<_U0:48, ?UUIDv1:4, _U1:12, ?VARIANT10:2,
                   ClockSeqLow:8, ClockSeqHi:6, NilNode/binary>>,
                 uuid:uuid1(NilNode, ClockSeq)),

    ?assertMatch(<<_U0:48, ?UUIDv3:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid3(dns, "fqdn.example.com")),
    ?assertEqual(uuid:uuid3(dns, "fqdn.example.com"),
                 uuid:uuid3(dns, "fqdn.example.com")),

    ?assertMatch(<<_U0:48, ?UUIDv3:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid3(oid, "2.5.6")),
    ?assertEqual(uuid:uuid3(oid, "2.5.6"), uuid:uuid3(oid, "2.5.6")),

    ?assertMatch(<<_U0:48, ?UUIDv3:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid3(url, "")),
    ?assertEqual(uuid:uuid3(url, ""),
                 uuid:uuid3(url, "")),

    ?assertMatch(<<_U0:48, ?UUIDv3:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid3(x500, "cn=John Doe, o=Acme, Inc., c=US")),
    ?assertEqual(uuid:uuid3(x500, "cn=John Doe, o=Acme, Inc., c=US"),
                 uuid:uuid3(x500, "cn=John Doe, o=Acme, Inc., c=US")),

    ?assertMatch(<<_U0:48, ?UUIDv3:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid3(nil, "my own unique name")),
    ?assertEqual(uuid:uuid3(nil, "my own unique name"),
                 uuid:uuid3(nil, "my own unique name")),

    ?assertMatch(<<_U0:48, ?UUIDv3:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid3(Uuid, "fqdn.example.com")),
    ?assertEqual(uuid:uuid3(Uuid, "fqdn.example.com"),
                 uuid:uuid3(Uuid, "fqdn.example.com")),

    ?assertMatch(<<_U0:48, ?UUIDv3:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid3(uuid:to_string(Uuid), "fqdn.example.com")),
    ?assertEqual(uuid:uuid3(uuid:to_string(Uuid), "fqdn.example.com"),
                 uuid:uuid3(uuid:to_string(Uuid), "fqdn.example.com")),

    ?assertMatch(<<_U0:48, ?UUIDv4:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid4()),

    ?assertMatch(<<_U0:48, ?UUIDv5:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid5(dns, "fqdn.example.com")),
    ?assertEqual(uuid:uuid5(dns, "fqdn.example.com"),
                 uuid:uuid5(dns, "fqdn.example.com")),

    ?assertMatch(<<_U0:48, ?UUIDv5:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid5(oid, "2.5.6")),
    ?assertEqual(uuid:uuid5(oid, "2.5.6"), uuid:uuid5(oid, "2.5.6")),

    ?assertMatch(<<_U0:48, ?UUIDv5:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid5(url, "")),
    ?assertEqual(uuid:uuid5(url, ""),
                 uuid:uuid5(url, "")),

    ?assertMatch(<<_U0:48, ?UUIDv5:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid5(x500, "cn=John Doe, o=Acme, Inc., c=US")),
    ?assertEqual(uuid:uuid5(x500, "cn=John Doe, o=Acme, Inc., c=US"),
                 uuid:uuid5(x500, "cn=John Doe, o=Acme, Inc., c=US")),

    ?assertMatch(<<_U0:48, ?UUIDv5:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid5(nil, "my own unique name")),
    ?assertEqual(uuid:uuid5(nil, "my own unique name"),
                 uuid:uuid5(nil, "my own unique name")),

    ?assertMatch(<<_U0:48, ?UUIDv5:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid5(Uuid, "fqdn.example.com")),
    ?assertEqual(uuid:uuid5(Uuid, "fqdn.example.com"),
                 uuid:uuid5(Uuid, "fqdn.example.com")),

    ?assertMatch(<<_U0:48, ?UUIDv5:4, _U1:12, ?VARIANT10:2, _U2:62>>,
                 uuid:uuid5(uuid:to_string(Uuid), "fqdn.example.com")),
    ?assertEqual(uuid:uuid5(uuid:to_string(Uuid), "fqdn.example.com"),
                 uuid:uuid5(uuid:to_string(Uuid), "fqdn.example.com")).

representation_test() ->
    Uuid1 = uuid:uuid1(),
    Uuid3 = uuid:uuid5(dns, "fqdn.example.com"),
    Uuid4 = uuid:uuid4(),
    Uuid5 = uuid:uuid5(dns, "fqdn.example.com"),
    ?assertMatch(Uuid1, uuid:to_binary(uuid:to_string(Uuid1))),
    ?assertMatch(Uuid3, uuid:to_binary(uuid:to_string(Uuid3))),
    ?assertMatch(Uuid4, uuid:to_binary(uuid:to_string(Uuid4))),
    ?assertMatch(Uuid5, uuid:to_binary(uuid:to_string(Uuid5))).

conversion_test() ->
    SimpleUuid = "8fd7fa874c205809a1b0e07f5c224f02",
    PrettyUuid = "8fd7fa87-4c20-5809-a1b0-e07f5c224f02",
    ?assertMatch(PrettyUuid,
                 uuid:to_string(uuid:uuid5(dns, "fqdn.example.com"))),
    ?assertMatch(PrettyUuid,
                 uuid:to_string(pretty, uuid:uuid5(dns, "fqdn.example.com"))),
    ?assertMatch(SimpleUuid,
                 uuid:to_string(simple, uuid:uuid5(dns, "fqdn.example.com"))),

    ?assertMatch(PrettyUuid,
                 uuid:to_string(uuid:to_binary(SimpleUuid))),
    ?assertMatch(SimpleUuid,
                 uuid:to_string(simple, uuid:to_binary(SimpleUuid))),
    ?assertMatch(PrettyUuid,
                 uuid:to_string(pretty, uuid:to_binary(PrettyUuid))).

exceptions_test() ->
    ?assertMatch(ok, try_badarg(to_binary, [0])),
    ?assertMatch(ok, try_badarg(to_string, [0])),
    ?assertMatch(ok, try_badarg(to_string, [0, 0])),
    ?assertMatch(ok, try_badarg(uuid3,     [0, 0])),
    ?assertMatch(ok, try_badarg(uuid5,     [0, 0])),
    ?assertMatch(ok, try_badarg(version,   [0])).

urn_test() ->
    UuidBin = uuid:uuid4(),
    UrnBin  = uuid:to_uuid_urn(UuidBin),
    UuidStr = uuid:to_string(UuidBin),
    UrnStr  = uuid:to_uuid_urn(UuidStr),

    [$u,$r,$n,$:,$u,$u,$i,$d,$:|UrnUuidBinStr] = UrnBin,
    ?assertMatch(UrnUuidBinStr, uuid:to_string(UuidBin)),

    [$u,$r,$n,$:,$u,$u,$i,$d,$:|UrnUuidStr] = UrnStr,
    ?assertMatch(UrnUuidStr, UuidStr),

    ?assertMatch(UrnUuidBinStr, UrnUuidStr),

    ?assertMatch(UrnBin, uuid:to_uuid_urn(UrnBin)).

version_test() ->
    Uuid1 = uuid:uuid1(),
    Uuid3 = uuid:uuid3(nil, ""),
    Uuid4 = uuid:uuid4(),
    Uuid5 = uuid:uuid5(nil, ""),

    ?assertMatch(?UUIDv1, uuid:version(Uuid1)),
    ?assertMatch(?UUIDv3, uuid:version(Uuid3)),
    ?assertMatch(?UUIDv4, uuid:version(Uuid4)),
    ?assertMatch(?UUIDv5, uuid:version(Uuid5)),

    Uuids = [Uuid1, Uuid3, Uuid4, Uuid5],

    ?assertMatch([true, false, false, false],
                 lists:map(fun uuid:is_v1/1, Uuids)),

    ?assertMatch([false, true, false, false],
                 lists:map(fun uuid:is_v3/1, Uuids)),

    ?assertMatch([false, false, true, false],
                 lists:map(fun uuid:is_v4/1, Uuids)),

    ?assertMatch([false, false, false, true],
                 lists:map(fun uuid:is_v5/1, Uuids)),

    ?assertMatch([rfc4122, rfc4122, rfc4122, rfc4122],
                 lists:map(fun uuid:variant/1, Uuids)),
    ?assertMatch([true, true, true, true],
                 lists:map(fun uuid:is_valid/1, Uuids)),

    ?assertMatch([reserved_ncs, reserved_microsoft, reserved_future],
                 lists:map(fun uuid:variant/1,
                           [<<0:64, 0:1, 0:1, 0:1, 0:61>>,
                            <<0:64, 1:1, 1:1, 0:1, 0:61>>,
                            <<0:64, 1:1, 1:1, 1:1, 0:61>>])),

    ?assertMatch(false, uuid:is_valid(<<1:128>>)),
    ?assertMatch(true, uuid:is_valid(<<0:128>>)).

stress_test_() ->
    {inparallel,
     {"uuid4 stress test.", {timeout, 10000, uuid4_stress()}}}.

uuid4_stress() ->
    Count = 100000,
    Uuids = [uuid:uuid4() || _ <- lists:seq(1, Count)],
    Uniqs = lists:usort(Uuids),
    ?_assertEqual(Count, length(Uniqs)).

do_randomized_and_timebased_uuids_change_enough_test() ->
    uuid_mask(fun uuid:uuid1/0, "^...XXXXX-....-1...-XXXX-............$"),
    uuid_mask(fun uuid:uuid4/0, "^XXXXXXXX-XXXX-4XXX-XXXX-XXXXXXXXXXXX$").

uuid_mask(F, Mask) ->
    ?assertEqual({match,[{0,36}]},
        re:run(do_uuid_mask(F, 100), Mask)).

do_uuid_mask(F, N) ->
    lists:foldl(fun mask/2,
        uuid:to_string(F()),
        [uuid:to_string(F()) || _ <- lists:seq(1,N)]).

mask(X, Y) -> lists:map(fun eq_or_x/1, lists:zip(X, Y)).

eq_or_x({X, X}) -> X;
eq_or_x(_) -> $X.

try_badarg(F, A) ->
    try
        apply(uuid, F, A)
    catch error:badarg ->
        ok
    end.
