MersenneTwisterTest.php
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MersenneTwisterTest.php
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	<?php
	namespace Eris\Random;

	class MersenneTwisterTest extends \PHPUnit\Framework\TestCase
	{
	public function setUp(): void
	{
	if (defined('HHVM_VERSION')) {
	$this->markTestSkipped('MersenneTwister class does not support HHVM');
	}
	$this->enableAssertions();
	}

	public function tearDown(): void
	{
	$this->disableAssertions();
	}

	public static function sequences()
	{
	return [
	[424242, 100],
	[0, 100],
	[0xffffffff, 100],
	[0xfffffffffffffff, 100],
	];
	}

	/**
	* @dataProvider sequences
	*/
	public function testGeneratesTheSameSequenceAsThePythonOracle($seed, $sample)
	{
	$twister = new MersenneTwister();
	$twister->seed($seed);
	$numbers = [];
	for ($i = 0; $i < $sample; $i++) {
	$numbers[$i] = $twister->extractNumber();
	}
	$oracle = "python " . __DIR__ . "/mt.py $seed $sample";
	exec($oracle, $oracleOutput, $returnCode);
	$this->assertEquals(0, $returnCode);
	$this->assertEquals($oracleOutput, $numbers);
	}

	public function testDistribution()
	{
	$twister = new MersenneTwister();
	$twister->seed(424242);
	$bins = array_fill(0, 2, 0);
	for ($i = 0; $i < 1000; $i++) {
	$number = $twister->extractNumber();
	$bin = (int) floor($number / pow(2, 31));
	$bins[$bin]++;
	}
	foreach ($bins as $count) {
	$this->assertGreaterThan(400, $count);
	}
	}

	private function enableAssertions()
	{
	assert_options(ASSERT_ACTIVE, 1);
	assert_options(ASSERT_CALLBACK, function ($file, $line, $code) {
	throw new \LogicException($code);
	});
	}

	private function disableAssertions()
	{
	assert_options(ASSERT_ACTIVE, 0);
	}
	}