public void Can_Claim_Present() { var idOfCreator = Guid.NewGuid(); var secondPersonid = Guid.NewGuid(); var presentId = Guid.NewGuid(); var wishlist = new WishlistBuilder(idOfCreator) .AddPerson(secondPersonid) .AddPerson(idOfCreator) .AddPresentIdea(idOfCreator, "asd", presentId) .Build(); var presentIdea = wishlist.GetPerson(idOfCreator).PresentIdeas.Single(); wishlist.ClaimGift(presentIdea.Id, secondPersonid); presentIdea.ClaimerId.Should().Be(secondPersonid); }