MathPHP\Statistics\Regression\LinearTest::testGetXs PHP Method

    public function testGetXs()
    {
        $points = [[1, 2], [2, 3], [4, 5], [5, 7], [6, 8]];
        $regression = new Linear($points);
        $this->assertEquals([1, 2, 4, 5, 6], $regression->getXs());
    }