PhpSpreadsheet/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/ForecastTest.php

<?php

declare(strict_types=1);

namespace PhpOffice\PhpSpreadsheetTests\Calculation\Functions\Statistical;

use PhpOffice\PhpSpreadsheet\Calculation\Calculation;
use PhpOffice\PhpSpreadsheet\Calculation\Statistical;
use PHPUnit\Framework\TestCase;

// TODO Spreadsheet context.
// Note that null in reference is treated differently than null in array.
class ForecastTest extends TestCase
{
    #[\PHPUnit\Framework\Attributes\DataProvider('providerFORECAST')]
    public function testFORECAST(mixed $expectedResult, mixed ...$args): void
    {
        $result = Statistical\Trends::FORECAST(...$args);
        self::assertEqualsWithDelta($expectedResult, $result, 1E-12);
    }

    public static function providerFORECAST(): array
    {
        return require 'tests/data/Calculation/Statistical/FORECAST.php';
    }

    #[\PHPUnit\Framework\Attributes\DataProvider('providerForecastArray')]
    public function testForecastArray(array $expectedResult, string $testValues, string $yValues, string $xValues): void
    {
        $calculation = Calculation::getInstance();

        $formula = "=FORECAST({$testValues}, {$yValues}, {$xValues})";
        $result = $calculation->calculateFormula($formula);
        self::assertEqualsWithDelta($expectedResult, $result, 1.0e-14);
    }

    public static function providerForecastArray(): array
    {
        return [
            'row vector' => [[[-11.047619047619047, 22.95238095238095, 42.38095238095237]], '{-2, 5, 9}', '{3, 7, 15, 20, 22, 27}', '{1, 2, 3, 4, 5, 6}'],
            'column vector' => [[[-11.047619047619047], [22.95238095238095], [42.38095238095237]], '{-2; 5; 9}', '{3, 7, 15, 20, 22, 27}', '{1, 2, 3, 4, 5, 6}'],
            'matrix' => [[[-11.047619047619047, 22.95238095238095], [42.38095238095237, 15.66666666666666]], '{-2, 5; 9, 3.5}', '{3, 7, 15, 20, 22, 27}', '{1, 2, 3, 4, 5, 6}'],
        ];
    }
}