FloatGeneratorTest.php
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FloatGeneratorTest.php
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	<?php
	namespace Eris\Generator;

	use Eris\PHPUnitDeprecationHelper;
	use Eris\Random\RandomRange;
	use Eris\Random\RandSource;

	class FloatGeneratorTest extends \PHPUnit\Framework\TestCase
	{
	/**
	* @var int
	*/
	private $size;
	/**
	* @var RandomRange
	*/
	private $rand;

	protected function setUp(): void
	{
	$this->size = 300;
	$this->rand = new RandomRange(new RandSource());
	}

	public function testPicksUniformelyPositiveAndNegativeFloatNumbers(): void
	{
	$generator = new FloatGenerator();
	$sum = 0;
	$trials = 500;
	for ($i = 0; $i < $trials; $i++) {
	$value = $generator($this->size, $this->rand);
	PHPUnitDeprecationHelper::assertIsFloat($value->unbox());
	$sum += $value->unbox();
	}
	$mean = $sum / $trials;
	// over a 300 size
	$this->assertLessThan(10, abs($mean));
	}

	public function testShrinksLinearly(): void
	{
	$generator = new FloatGenerator();
	$this->assertSame(3.5, $generator->shrink(GeneratedValueSingle::fromJustValue(4.5))->unbox());
	$this->assertSame(-2.5, $generator->shrink(GeneratedValueSingle::fromJustValue(-3.5))->unbox());
	}

	public function testWhenBothSignsArePossibleCannotShrinkBelowZero(): void
	{
	$generator = new FloatGenerator();
	$this->assertSame(0.0, $generator->shrink(GeneratedValueSingle::fromJustValue(0.0))->unbox());
	$this->assertSame(0.0, $generator->shrink(GeneratedValueSingle::fromJustValue(0.5))->unbox());
	$this->assertSame(0.0, $generator->shrink(GeneratedValueSingle::fromJustValue(-0.5))->unbox());
	}
	}