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 // Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file // for details. All rights reserved. Use of this source code is governed by a // BSD-style license that can be found in the LICENSE file. // @dart = 2.9 // Test that rnd.nextInt with a seed generates the same sequence each time. // Library tag to allow Dartium to run the test. library random_test; import "package:expect/expect.dart"; import 'dart:math'; main() { checkSequence(); checkSeed(); } void checkSequence() { // Check the sequence of numbers generated by the random generator for a seed // doesn't change unintendedly, and it agrees between implementations. var rnd = new Random(20130307); // Make sure we do not break the random number generation. // If the random algorithm changes, make sure both the VM and dart2js // generate the same new sequence. var i = 1; Expect.equals(0, rnd.nextInt(i *= 2)); Expect.equals(3, rnd.nextInt(i *= 2)); Expect.equals(7, rnd.nextInt(i *= 2)); Expect.equals(5, rnd.nextInt(i *= 2)); Expect.equals(29, rnd.nextInt(i *= 2)); Expect.equals(17, rnd.nextInt(i *= 2)); Expect.equals(104, rnd.nextInt(i *= 2)); Expect.equals(199, rnd.nextInt(i *= 2)); Expect.equals(408, rnd.nextInt(i *= 2)); Expect.equals(362, rnd.nextInt(i *= 2)); Expect.equals(995, rnd.nextInt(i *= 2)); Expect.equals(2561, rnd.nextInt(i *= 2)); Expect.equals(2548, rnd.nextInt(i *= 2)); Expect.equals(9553, rnd.nextInt(i *= 2)); Expect.equals(2628, rnd.nextInt(i *= 2)); Expect.equals(42376, rnd.nextInt(i *= 2)); Expect.equals(101848, rnd.nextInt(i *= 2)); Expect.equals(85153, rnd.nextInt(i *= 2)); Expect.equals(495595, rnd.nextInt(i *= 2)); Expect.equals(647122, rnd.nextInt(i *= 2)); Expect.equals(793546, rnd.nextInt(i *= 2)); Expect.equals(1073343, rnd.nextInt(i *= 2)); Expect.equals(4479969, rnd.nextInt(i *= 2)); Expect.equals(9680425, rnd.nextInt(i *= 2)); Expect.equals(28460171, rnd.nextInt(i *= 2)); Expect.equals(49481738, rnd.nextInt(i *= 2)); Expect.equals(9878974, rnd.nextInt(i *= 2)); Expect.equals(132552472, rnd.nextInt(i *= 2)); Expect.equals(210267283, rnd.nextInt(i *= 2)); Expect.equals(125422442, rnd.nextInt(i *= 2)); Expect.equals(226275094, rnd.nextInt(i *= 2)); Expect.equals(1639629168, rnd.nextInt(i *= 2)); Expect.equals(0x100000000, i); // If max is too large expect an ArgumentError. Expect.throwsArgumentError(() => rnd.nextInt(i + 1)); rnd = new Random(6790); Expect.approxEquals(0.1202733131, rnd.nextDouble()); Expect.approxEquals(0.5554054805, rnd.nextDouble()); Expect.approxEquals(0.0385160727, rnd.nextDouble()); Expect.approxEquals(0.2836345217, rnd.nextDouble()); } void checkSeed() { // Check that various seeds generate the expected first values. // 53 significant bits, so the number is representable in JS. var rawSeed = 0x19a32c640e1d71; var expectations = [ 26007, 43006, 46458, 18610, 16413, 50455, 2164, 47399, 8859, 9732, 20367, 33935, 54549, 54913, 4819, 24198, 49353, 22277, 51852, 35959, 45347, 12100, 10136, 22372, 15293, 20066, 1351, 49030, 64845, 12793, 50916, 55784, 43170, 27653, 34696, 1492, 50255, 9597, 45929, 2874, 27629, 53084, 36064, 42140, 32016, 41751, 13967, 20516, 578, 16773, 53064, 14814, 22737, 48846, 45147, 10205, 56584, 63711, 44128, 21099, 47966, 35471, 39576, 1141, 45716, 54940, 57406, 15437, 31721, 35044, 28136, 39797, 50801, 22184, 58686 ]; var negative_seed_expectations = [ 12170, 42844, 39228, 64032, 29046, 57572, 8453, 52224, 27060, 28454, 20510, 28804, 59221, 53422, 11047, 50864, 33997, 19611, 1250, 65088, 19690, 11396, 20, 48867, 44862, 47129, 58724, 13325, 50005, 33320, 16523, 4740, 63721, 63272, 30545, 51403, 35845, 3943, 31850, 23148, 26307, 1724, 29281, 39988, 43653, 48012, 43810, 16755, 13105, 25325, 32648, 19958, 38838, 8322, 3421, 28624, 17269, 45385, 50680, 1696, 26088, 2787, 48566, 34357, 27731, 51764, 8455, 16498, 59721, 59568, 46333, 7935, 51459, 36766, 50711 ]; for (var i = 0, m = 1; i < 75; i++) { if (rawSeed * m < 0) { // Overflow. break; } Expect.equals(expectations[i], new Random(rawSeed * m).nextInt(65536)); Expect.equals( negative_seed_expectations[i], new Random(rawSeed * -m).nextInt(65536)); m *= 2; } // And test zero seed too. Expect.equals(21391, new Random(0).nextInt(65536)); }