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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.