public void GivenAdd_WhenAddBook_ShouldReturnBooksListWithNewBook()
        {
            // Arrange
            Book bookToAdd = new Book {
                Name = "Herbert Schildt C#"
            };

            var bookFileStorage = new BookFileStorage(_settings);

            // Act
            bookFileStorage.Add(bookToAdd);
            var books = bookFileStorage.GetAll();

            // Assert
            books.Should().BeEquivalentTo(new List <Book>
            {
                new Book {
                    Id = 1, Name = "The Lord of the Rings"
                },
                new Book {
                    Id = 2, Name = "Le Petit Prince"
                },
                new Book {
                    Id = 3, Name = "Harry Potter and the Philosopher's Stone"
                },
                new Book {
                    Id = 4, Name = "The Hobbit"
                },
                new Book {
                    Id = 5, Name = "Herbert Schildt C#"
                }
            });
        }
        public void GivenAdd_WhenBookIsNull_ShouldReturnException()
        {
            // Arrange
            var bookFileStorage = new BookFileStorage(_settings);

            //Act
            TestDelegate testAction = () => bookFileStorage.Add(null);

            //Assert
            var ex = Assert.Throws <InvalidOperationException>(testAction);

            Assert.That(ex.Message, Is.EqualTo("Can not add null object!"));
        }