public void GetInvoiceHeaderEntityByIdFromDatabase()
        {
            IInvoice invoiceHeader = new Invoice
            {
                CustomerId = 1,
                SupplierId = 2,
                InvoiceNumber = 10
            };

            IInvoiceDao invoiceDao = new InvoiceDao(_sqlConnection);

            invoiceDao.Write(invoiceHeader);

            invoiceDao = new InvoiceDao(_sqlConnection);

            invoiceHeader = invoiceDao.GetById(invoiceHeader.Id);

            Assert.IsTrue(invoiceHeader != null);
        }