public async Task CheckOutBooksRetunsBadRequestWithABadBookId()
        {
            var bookService = new Mock<IBooksService>();
            var controller = new BooksController(bookService.Object);

            var result = await controller.CheckoutBook(null) as BadRequestErrorMessageResult;

            Assert.AreEqual("Invalid bookId", result.Message);
        }
        public async Task CheckedOutBooksReturnsBookNotFound()
        {
            var bookServiceMock = new Mock<IBooksService>();
            bookServiceMock.Setup(bs => bs.CheckOutBook(It.IsAny<int>()))
                .ReturnsAsync(new CheckedOutBookDTO { State = CheckedOutBookState.BookNotFound });


            var controller = new BooksController(bookServiceMock.Object);

            var result = await controller.CheckoutBook(1) as BadRequestErrorMessageResult;

            Assert.AreEqual("This book does not exist at this library", result.Message);
        }
        public async Task CheckedOutBooksReturnsTooManyBooksCheckedOut()
        {
            var bookServiceMock = new Mock<IBooksService>();
            bookServiceMock.Setup(bs => bs.CheckOutBook(It.IsAny<int>()))
                .ReturnsAsync(new CheckedOutBookDTO { State = CheckedOutBookState.TooManyBooksCheckedOut });


            var controller = new BooksController(bookServiceMock.Object);

            var result = await controller.CheckoutBook(1) as BadRequestErrorMessageResult;

            Assert.AreEqual("User has too many books checked out", result.Message);
        }
        public async Task CheckedOutBooksReturnsBookIsNotAvailable()
        {
            var bookServiceMock = new Mock<IBooksService>();
            var userServiceMock = new Mock<IUserService>();

            bookServiceMock.Setup(bs => bs.CheckOutBook(It.IsAny<int>()))
                .ReturnsAsync(new CheckedOutBookDTO { State = CheckedOutBookState.BookIsNotAvailable });


            var controller = new BooksController(bookServiceMock.Object);

            var result = await controller.CheckoutBook(1) as BadRequestErrorMessageResult;

            Assert.AreEqual("This book has no more copies to check out", result.Message);
        }
        public async Task CheckedOutBooksReturnsSuccess()
        {
            var bookServiceMock = new Mock<IBooksService>();
            var checkedOutBook = new CheckedOutBookDTO
            {
                State = CheckedOutBookState.Success
            };
            bookServiceMock.Setup(bs => bs.CheckOutBook(It.IsAny<int>()))
                .ReturnsAsync(checkedOutBook);


            var controller = new BooksController(bookServiceMock.Object);

            var result = await controller.CheckoutBook(1) as OkResult;

            Assert.IsNotNull(result);
        }