Harry Terkelsen
382996f41c
BUG= R=rnystrom@google.com Review URL: https://codereview.chromium.org/1967773005 .
102 lines
4.4 KiB
Dart
102 lines
4.4 KiB
Dart
// Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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// Test that rnd.nextInt with a seed generates the same sequence each time.
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// Library tag to allow Dartium to run the test.
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library random_test;
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import "package:expect/expect.dart";
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import 'dart:math';
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main() {
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checkSequence();
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checkSeed();
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}
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void checkSequence() {
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// Check the sequence of numbers generated by the random generator for a seed
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// doesn't change unintendedly, and it agrees between implementations.
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var rnd = new Random(20130307);
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// Make sure we do not break the random number generation.
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// If the random algorithm changes, make sure both the VM and dart2js
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// generate the same new sequence.
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var i = 1;
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Expect.equals( 0, rnd.nextInt(i *= 2));
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Expect.equals( 3, rnd.nextInt(i *= 2));
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Expect.equals( 7, rnd.nextInt(i *= 2));
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Expect.equals( 5, rnd.nextInt(i *= 2));
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Expect.equals( 29, rnd.nextInt(i *= 2));
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Expect.equals( 17, rnd.nextInt(i *= 2));
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Expect.equals( 104, rnd.nextInt(i *= 2));
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Expect.equals( 199, rnd.nextInt(i *= 2));
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Expect.equals( 408, rnd.nextInt(i *= 2));
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Expect.equals( 362, rnd.nextInt(i *= 2));
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Expect.equals( 995, rnd.nextInt(i *= 2));
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Expect.equals( 2561, rnd.nextInt(i *= 2));
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Expect.equals( 2548, rnd.nextInt(i *= 2));
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Expect.equals( 9553, rnd.nextInt(i *= 2));
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Expect.equals( 2628, rnd.nextInt(i *= 2));
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Expect.equals( 42376, rnd.nextInt(i *= 2));
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Expect.equals( 101848, rnd.nextInt(i *= 2));
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Expect.equals( 85153, rnd.nextInt(i *= 2));
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Expect.equals( 495595, rnd.nextInt(i *= 2));
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Expect.equals( 647122, rnd.nextInt(i *= 2));
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Expect.equals( 793546, rnd.nextInt(i *= 2));
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Expect.equals( 1073343, rnd.nextInt(i *= 2));
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Expect.equals( 4479969, rnd.nextInt(i *= 2));
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Expect.equals( 9680425, rnd.nextInt(i *= 2));
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Expect.equals( 28460171, rnd.nextInt(i *= 2));
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Expect.equals( 49481738, rnd.nextInt(i *= 2));
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Expect.equals( 9878974, rnd.nextInt(i *= 2));
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Expect.equals( 132552472, rnd.nextInt(i *= 2));
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Expect.equals( 210267283, rnd.nextInt(i *= 2));
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Expect.equals( 125422442, rnd.nextInt(i *= 2));
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Expect.equals( 226275094, rnd.nextInt(i *= 2));
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Expect.equals(1639629168, rnd.nextInt(i *= 2));
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Expect.equals(0x100000000, i);
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// If max is too large expect an ArgumentError.
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Expect.throws(() => rnd.nextInt(i + 1), (e) => e is ArgumentError);
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rnd = new Random(6790);
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Expect.approxEquals(0.1202733131, rnd.nextDouble());
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Expect.approxEquals(0.5554054805, rnd.nextDouble());
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Expect.approxEquals(0.0385160727, rnd.nextDouble());
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Expect.approxEquals(0.2836345217, rnd.nextDouble());
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}
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void checkSeed() {
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// Check that various seeds generate the expected first values.
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// 53 significant bits, so the number is representable in JS.
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var rawSeed = 0x19a32c640e1d71;
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var expectations = [
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26007, 43006, 46458, 18610, 16413, 50455, 2164, 47399, 8859, 9732,
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20367, 33935, 54549, 54913, 4819, 24198, 49353, 22277, 51852, 35959,
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45347, 12100, 10136, 22372, 15293, 20066, 1351, 49030, 64845, 12793,
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50916, 55784, 43170, 27653, 34696, 1492, 50255, 9597, 45929, 2874,
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27629, 53084, 36064, 42140, 32016, 41751, 13967, 20516, 578, 16773,
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53064, 14814, 22737, 48846, 45147, 10205, 56584, 63711, 44128, 21099,
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47966, 35471, 39576, 1141, 45716, 54940, 57406, 15437, 31721, 35044,
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28136, 39797, 50801, 22184, 58686
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];
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var negative_seed_expectations = [
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12170, 42844, 39228, 64032, 29046, 57572, 8453, 52224, 27060, 28454,
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20510, 28804, 59221, 53422, 11047, 50864, 33997, 19611, 1250, 65088,
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19690, 11396, 20, 48867, 44862, 47129, 58724, 13325, 50005, 33320,
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16523, 4740, 63721, 63272, 30545, 51403, 35845, 3943, 31850, 23148,
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26307, 1724, 29281, 39988, 43653, 48012, 43810, 16755, 13105, 25325,
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32648, 19958, 38838, 8322, 3421, 28624, 17269, 45385, 50680, 1696,
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26088, 2787, 48566, 34357, 27731, 51764, 8455, 16498, 59721, 59568,
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46333, 7935, 51459, 36766, 50711
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];
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for (var i = 0, m = 1; i < 75; i++) {
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Expect.equals(expectations[i], new Random(rawSeed * m).nextInt(65536));
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Expect.equals(negative_seed_expectations[i],
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new Random(rawSeed * -m).nextInt(65536));
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m *= 2;
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}
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// And test zero seed too.
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Expect.equals(21391, new Random(0).nextInt(65536));
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}
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