Chromium Code Reviews| Index: tests/lib/math/low_test.dart |
| =================================================================== |
| --- tests/lib/math/low_test.dart (revision 0) |
| +++ tests/lib/math/low_test.dart (revision 0) |
| @@ -0,0 +1,31 @@ |
| +// Copyright (c) 2012, 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 the default PRNG does uniformly distribute values when not using |
| +// a power of 2. |
| + |
| +// Library tag to allow Dartium to run the test. |
| +#library("low_test.dart"); |
| + |
| +#import("dart:math"); |
| + |
| +void main() { |
| + var n = (2 * (1<<32)) ~/ 3; |
| + var n2 = n ~/ 2; |
| + |
| + var iterations = 200000; |
| + |
| + var prng = new Random(); |
| + |
| + var low = 0; |
| + for (var i = 0; i < iterations; i++) { |
| + if (prng.nextInt(n) < n2) { |
| + low++; |
| + } |
| + } |
| + |
| + var diff = (low - (iterations ~/ 2)).abs(); |
| + print("$low, $diff"); |
|
kasperl
2012/05/23 12:40:46
Debug printing?
|
| + Expect.isTrue(diff < (iterations ~/ 20)); |
| +} |