public function testGetTotalPriceExcludingTax()
{
$item = new CartItem();
$item->price = 10.0;
$item->tax = 5.0;
$item->quantity = 2;
$price = $item->getTotalPriceExcludingTax();
$this->assertEquals(20.0, $price);
$this->assertTrue(is_float($price));
}
