public void BorrowExistingBookToCustomerWithMoney()
        {
            Books book = new Books()
            {
                id = 201, author = "Jane Austin", title = "Awesome book", type = "Classic", penaltyCost = 20, state = 1
            };

            Assert.IsTrue(BookCRUD.addBook(book.id, book.title, book.author, book.type, book.penaltyCost, DateTime.Today, (int)book.state));
            Customers c = new Customers()
            {
                id = 201, name = "Paul", money = 100
            };

            Assert.IsTrue(CustomerCRUD.addCustomer(c.id, c.name, c.money));
            Assert.IsTrue(BorrowedBookCRUD.borrowBook(101, c.id, book.id));
            Assert.AreEqual(BookCRUD.getBook(book.id).returnDate, DateTime.Today.AddDays(14));
            Assert.AreEqual(BorrowedBookCRUD.getBorrowedBooks(book.id).customerId, c.id);
        }