How design patterns can help you in developing unit testing-enabled applications

using Castle.ActiveRecord;
using Castle.ActiveRecord.Framework;
using Castle.ActiveRecord.Queries;
using NHibernate;
using NHibernate.Expression;
using Northwind.Domain;
using System;
using System.Collections.Generic;
using System.Text;

namespace Northwind.Domain.Model
{
    /// <summary>
    /// This domain model class is mapped to the Orders table of Northwind database for Castle Project ActiveRecorrd framework.
    /// Besides, it is also mapped to the OrderTO transfer class.
    /// </summary>
    [ActiveRecord("Orders")]
    [MappedTO("Northwind.TransferObjects.Model.OrderTO")]
    public class Order : DomainBase<int>
    {
        int orderID;
        string customerID;
        int? employeeID;
        DateTime? orderDate;
        DateTime? requiredDate;
        DateTime? shippedDate;
        int? shipVia;
        float? freight;
        string shipName;
        string shipAddress;
        string shipCity;
        string shipRegion;
        string shipPostalCode;
        string shipCountry;

        public Order()
        {
        }

        [PrimaryKey(Column = "OrderID", Generator = PrimaryKeyType.Identity)]
        public override int ID
        {
            get {return orderID; }
            set { orderID = value; }
        }

        [Property()]
        public string CustomerID
        {
            get { return customerID; }
            set { customerID = value; }
        }

        [Property()]
        public int? EmployeeID
        {
            get { return employeeID; }
            set { employeeID = value; }
        }

        [Property()]
        public DateTime? OrderDate
        {
            get { return orderDate; }
            set { orderDate = value; }
        }

        [Property()]
        public DateTime? RequiredDate
        {
            get { return requiredDate; }
            set { requiredDate = value; }
        }

        [Property()]
        public DateTime? ShippedDate
        {
            get { return shippedDate; }
            set { shippedDate = value; }
        }

        [Property()]
        public int? ShipVia
        {
            get { return shipVia; }
            set { shipVia = value; }
        }

        [Property()]
        public float? Freight
        {
            get { return freight; }
            set { freight = value; }
        }

        [Property()]
        public string ShipName
        {
            get { return shipName; }
            set { shipName = value; }
        }

        [Property()]
        public string ShipAddress
        {
            get { return shipAddress; }
            set { shipAddress = value; }
        }

        [Property()]
        public string ShipCity
        {
            get { return shipCity; }
            set { shipCity = value; }
        }

        [Property()]
        public string ShipRegion
        {
            get { return shipRegion; }
            set { shipRegion = value; }
        }

        [Property()]
        public string ShipPostalCode
        {
            get { return shipPostalCode; }
            set { shipPostalCode = value; }
        }

        [Property()]
        public string ShipCountry
        {
            get { return shipCountry; }
            set { shipCountry = value; }
        }
    }
}