public void ClearBasket()
{
// arrange
var sut = new BasketOfItems(1);
sut.AddUpdateOrRemoveItem(1, 1);
sut.AddUpdateOrRemoveItem(2, 3);
// act
sut.ClearBasket();
//assert
Assert.That(sut.Id, Is.GreaterThan(0));
Assert.That(sut.CustomerId, Is.EqualTo(1));
Assert.That(sut.BasketItems, Is.Empty);
}