public async Task get_book_with_not_existing_isbn()
        {
            var repository = BookContextMocker.GetInMemoryBooksRepository(nameof(get_book_with_not_existing_isbn));
            var controller = new BookController(repository);

            var response = await controller.Get(1234567) as ObjectResult;

            var book = response.Value as Book;

            Assert.Equal(200, response.StatusCode);
            Assert.Equal(null, book);
        }
        public async Task get_book_with_existing_isbn()
        {
            var repository    = BookContextMocker.GetInMemoryBooksRepository(nameof(get_book_with_existing_isbn));
            var controller    = new BookController(repository);
            var expectedValue = "Harry Potter";

            var response = await controller.Get(123456) as ObjectResult;

            var book = response.Value as Book;

            Assert.Equal(200, response.StatusCode);
            Assert.Equal(expectedValue, book.Title);
        }
        public async Task get_all_books()
        {
            var repository = BookContextMocker.GetInMemoryBooksRepository(nameof(get_all_books));
            var controller = new BookController(repository);


            var response = await controller.GetAll() as ObjectResult;

            var books = response.Value as List <Book>;


            Assert.Equal(200, response.StatusCode);
            Assert.Equal(5, books.Count);
        }