| // 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. |
| |
| // 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.throws(() => rnd.nextInt(i + 1), (e) => e is ArgumentError); |
| |
| 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++) { |
| 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)); |
| } |