public void GetInvoiceHeaderEntityBySqlFromDatabase()
        {
            IInvoice invoiceHeader = new Invoice
            {
                CustomerId = 1,
                SupplierId = 2,
                InvoiceNumber = 56
            };

            IInvoiceDao invoiceDao = new InvoiceDao(_sqlConnection);

            invoiceDao.Write(invoiceHeader);

            invoiceDao = new InvoiceDao(_sqlConnection);

            string sqlQuery = $"SELECT * FROM InvoiceHeader WHERE [Id] = {invoiceHeader.Id}";

            invoiceHeader = invoiceDao.GetBySql(sqlQuery);

            Assert.IsTrue(invoiceHeader != null);
        }