private static (Item item, RetrievedItem <Item> retrievedItem) GetExpectedItem()
        {
            const string creationTime = "2000-12-20";
            var          expectedItem = ItemsCreator.CreateItemAndRetrievedItem(
                id: "00000000-0000-0000-0000-000000000006",
                text: "text",
                creationTime: creationTime,
                lastUpdateTime: creationTime);

            return(expectedItem);
        }
        private static (RetrievedItem <Item> expectedItem, Item itemForUpdate) GetExpectedItemAndItemForUpdate()
        {
            const string lastUpdateTime = "2018-10-17";
            const string id             = "00000000-0000-0000-0000-000000000006";
            const string text           = "text";

            var itemForUpdate = ItemsCreator.CreateItem(id: id, text: text);

            var expectedItem = ItemsCreator
                               .CreateItemAndRetrievedItem(id: id, text: text, lastUpdateTime: lastUpdateTime)
                               .retrievedItem;

            return(expectedItem, itemForUpdate);
        }