public void GetAllBooks_ReturnsOk()
        {
            mockService.Setup(s => s.GetAllBooks())
            .Returns(BookTestData.GetAllBooksServiceResponse());

            BookController bookController = new BookController(mockService.Object);
            AddBookDto     newBook        = BookTestData.AddBookDto();

            bookController.AddBook(newBook);

            var result = bookController.Get();

            Assert.That(result, Is.InstanceOf <OkObjectResult>());
        }