public void Can_reduce_an_item_without_removing_it()
{
var box = new Box();
var item = new Item {Name = "Test Item"};
box.AddItem(2, item);
Assert.Equal(2, box.Contents.First(x => x.Item == item).Quantity);
box.ReduceItem(1, item);
Assert.Equal(1, box.Contents.First(x => x.Item == item).Quantity);
}
public void Reducing_an_item_by_equal_or_more_than_current_quantity_removes_item()
{
var box = new Box();
var item = new Item {Name = "Test Item"};
box.AddItem(2, item);
Assert.Equal(2, box.Contents.First(x => x.Item == item).Quantity);
box.ReduceItem(2, item);
Assert.Equal(0, box.Contents.Count(x => x.Item == item));
}
public void Passing_negative_quantity_to_reduce_item_throws_error()
{
var box = new Box();
Assert.Throws<InvalidOperationException>(() => box.ReduceItem(1, new Item()));
}