blob: 80022c7c890ef48cd97cbd8e76f46e3c5ed6d20e [file] [log] [blame]
// 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;
import "package:expect/expect.dart";
import 'dart:math';
void main() {
var n = (2 * (1 << 32)) ~/ 3;
var n2 = n ~/ 2;
var iterations = 200000;
var seed = new Random().nextInt(1 << 16);
print("low_test seed: $seed");
var prng = new Random(seed);
var low = 0;
for (var i = 0; i < iterations; i++) {
if (prng.nextInt(n) < n2) {
low++;
}
}
var diff = (low - (iterations ~/ 2)).abs();
print("$low, $diff");
Expect.isTrue(diff < (iterations ~/ 20));
}