public function testCreateDefaults()
{
$cart = new Cart();
$this->assertTrue($cart->getId() instanceof UuidInterface);
$this->assertTrue($cart->getCreated() instanceof DateTime);
$this->assertSame(null, $cart->getSessionId());
$this->assertSame(null, $cart->getUser());
$this->assertSame(null, $cart->getShippingAddress());
$this->assertSame(null, $cart->getShipmentRate());
$this->assertSame(null, $cart->getTaxRate());
$this->assertSame('0.0.0.0', $cart->getIp4());
$this->assertSame(0, count($cart->getCartItems()));
$this->assertSame(0, count($cart->getCoupons()));
}