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); }