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#!/usr/bin/env escript
%% -*- erlang -*-
% Licensed under the Apache License, Version 2.0 (the "License"); you may not
% use this file except in compliance with the License. You may obtain a copy of
% the License at
%
% http://www.apache.org/licenses/LICENSE-2.0
%
% Unless required by applicable law or agreed to in writing, software
% distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
% WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
% License for the specific language governing permissions and limitations under
% the License.
default_config() ->
test_util:build_file("etc/couchdb/default_dev.ini").
seq_alg_config() ->
test_util:source_file("test/etap/041-uuid-gen-seq.ini").
utc_alg_config() ->
test_util:source_file("test/etap/041-uuid-gen-utc.ini").
% Run tests and wait for the gen_servers to shutdown
run_test(IniFiles, Test) ->
{ok, Pid} = couch_config:start_link(IniFiles),
erlang:monitor(process, Pid),
couch_uuids:start(),
Test(),
couch_uuids:stop(),
couch_config:stop(),
receive
{'DOWN', _, _, Pid, _} -> ok;
_Other -> etap:diag("OTHER: ~p~n", [_Other])
after
1000 -> throw({timeout_error, config_stop})
end.
main(_) ->
test_util:init_code_path(),
application:start(crypto),
etap:plan(6),
case (catch test()) of
ok ->
etap:end_tests();
Other ->
etap:diag(io_lib:format("Test died abnormally: ~p", [Other])),
etap:bail(Other)
end,
ok.
test() ->
TestUnique = fun() ->
etap:is(
test_unique(10000, couch_uuids:new()),
true,
"Can generate 10K unique IDs"
)
end,
run_test([default_config()], TestUnique),
run_test([default_config(), seq_alg_config()], TestUnique),
run_test([default_config(), utc_alg_config()], TestUnique),
TestMonotonic = fun () ->
etap:is(
couch_uuids:new() < couch_uuids:new(),
true,
"should produce monotonically increasing ids"
)
end,
run_test([default_config(), seq_alg_config()], TestMonotonic),
run_test([default_config(), utc_alg_config()], TestMonotonic),
% Pretty sure that the average of a uniform distribution is the
% midpoint of the range. Thus, to exceed a threshold, we need
% approximately Total / (Range/2 + RangeMin) samples.
%
% In our case this works out to be 8194. (0xFFF000 / 0x7FF)
% These tests just fudge the limits for a good generator at 25%
% in either direction. Technically it should be possible to generate
% bounds that will show if your random number generator is not
% sufficiently random but I hated statistics in school.
TestRollOver = fun() ->
UUID = binary_to_list(couch_uuids:new()),
Prefix = element(1, lists:split(26, UUID)),
N = gen_until_pref_change(Prefix,0),
etap:diag("N is: ~p~n",[N]),
etap:is(
N >= 5000 andalso N =< 11000,
true,
"should roll over every so often."
)
end,
run_test([default_config(), seq_alg_config()], TestRollOver).
test_unique(0, _) ->
true;
test_unique(N, UUID) ->
case couch_uuids:new() of
UUID ->
etap:diag("N: ~p~n", [N]),
false;
Else -> test_unique(N-1, Else)
end.
get_prefix(UUID) ->
element(1, lists:split(26, binary_to_list(UUID))).
gen_until_pref_change(_, Count) when Count > 8251 ->
Count;
gen_until_pref_change(Prefix, N) ->
case get_prefix(couch_uuids:new()) of
Prefix -> gen_until_pref_change(Prefix, N+1);
_ -> N
end.
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