public void When_a_book_collection_with_no_books_is_asked_to_RemoveSet__should_remain_empty()
        {
            var bookCollection = new BookCollection(new Book[0]);

            var result = new BookSetDiscoverer().RemoveSet(bookCollection);

            Assert.AreEqual("", result.ToString());
        }
        public void When_a_book_collection_with_one_book_is_asked_to_RemoveSet__should_remove_the_one_book()
        {
            var bookCollection = new BookCollection(new[]
                                                        {
                                                            new Book(BookTitle.BookOne)
                                                        });

            var result = new BookSetDiscoverer().RemoveSet(bookCollection);

            Assert.AreEqual("", result.ToString());
        }