Pro Aspnet MVC 4读书笔记(2) - The MVC Pattern

Listing 3-1. The C# Auction Domain Model

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

namespace MvcPattern.Models

{

    public class Member

    {

        public string LoginName { get; set; } // The unique key

        public int ReputationPoints { get; set; }

    }

    public class Bid

    {

        public Member Member { get; set; }

        public DateTime DatePlaced { get; set; }

        public decimal BidAmount { get; set; }

    }

    public class Item

    {

        public int ItemID { get; private set; } // The unique key

        public string Title { get; set; }

        public string Description { get; set; }

        public DateTime AuctionEndDate { get; set; }

        public IList<Bid> Bids { get; set; }

    }

}

Listing 3-2. C# Repository Classes for the Member and Item Domain Classes

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

namespace MvcPattern.Models

{

    public class MembersRepository

    {

        public void AddMember(Member member)

        { }

        public Member FetchByLoginName(string loginName)

        {

            return null;

        }

        public void SubmitChanges()

        { }

    }

    public class ItemsRepository

    {

        public void AddItem(Item item)

        { }

        public Item FetchById(int itemId)

        {

            return null;

        }

        public IList<Item> ListItems(int pageSize, int pageIndex)

        {

            return null;

        }

        public void SubmitChanges()

        { }

    }

}

Listing 3-3. Instantiating Concrete Classes to Get an Interface Implementation

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

namespace MvcPattern.Models

{

    public class PasswordResetHelper

    {

        public void ResetPassword()

        {

            IEmailSender mySender = new MyEmailSender();

            // Call interface methods to configure e-mail details

            mySender.SendEmail();

        }

    }

}

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

namespace MvcPattern.Models

{

    public interface IEmailSender

    {

        void SendEmail();

    }

    public class MyEmailSender : IEmailSender

    {

        public void SendEmail()

        {

        }

    }

}

Listing 3-4. Removing Dependencies from the PasswordResetHelper Class

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

namespace MvcPattern.Models

{

    public class PasswordResetHelper

    {

        private IEmailSender _emailSender;

        public PasswordResetHelper(IEmailSender emailSender)

        {

            _emailSender = emailSender;

        }

        public void ResetPassword()

        {

            // Call interface methods to configure e-mail details

            _emailSender.SendEmail();

        }

    }

}

Listing 3-5. The IMembersRepository Interface

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

namespace MvcPattern.Models

{

    public interface IMembersRepository

    {

        void AddMember(Member member);

        Member FetchByLoginName(string loginName);

        void SubmitChanges();

    }

    public class MembersRepository : IMembersRepository

    {

        public void AddMember(Member member)

        { }

        public Member FetchByLoginName(string loginName)

        {

            return null;

        }

        public void SubmitChanges()

        { }

    }

}

Listing 3-6. The AdminController Class

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.Mvc;

using MvcPattern.Models;

namespace MvcPattern.Controllers

{

    public class AdminController : Controller

    {

        IMembersRepository _membersRepository;

        public AdminController(IMembersRepository membersRepository)

        {

            _membersRepository = membersRepository;

        }

        public ActionResult ChangeLoginName(string oldLoginName, string newLoginName)

        {

            Member member = _membersRepository.FetchByLoginName(oldLoginName);

            member.LoginName = newLoginName;

            _membersRepository.SubmitChanges();

            return View();

        }

    }

}

Listing 3-7. An Example Test Fixture

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using Microsoft.VisualStudio.TestTools.UnitTesting;

using MvcPattern.Controllers;

using MvcPattern.Models;

namespace MvcPattern.Tests

{

    [TestClass]

    public class AdminControllerTest

    {

        [TestMethod]

        public void CanChangeLoginName()

        {

            // Arrange (set up a scenario)

            Member bob = new Member() { LoginName = "Bob" };

            FakeMembersRepository repository = new FakeMembersRepository();

            repository.Members.Add(bob);

            AdminController target = new AdminController(repository);

            string oldLoginName = bob.LoginName;

            string newLoginName = "Anastasia";

            // Act (attempt the operation)

            target.ChangeLoginName(oldLoginName, newLoginName);

            // Assert (verify the result)

            Assert.AreEqual(newLoginName, bob.LoginName);

            Assert.IsTrue(repository.DidSubmitChanges);

        }

    }

    private class FakeMembersRepository : IMembersRepository

    {

        public List<Member> Members = new List<Member>();

        public bool DidSubmitChanges = false;

        public void AddMember(Member member)

        {

        }

        public Member FetchByLoginName(string loginName)

        {

            return Members.First(m => m.LoginName == loginName);

        }

        public void SubmitChanges()

        {

            DidSubmitChanges = true;

        }

    }

}

Listing 3-8. Adding a Stub Method to the Item Class

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

namespace MvcPattern.Models

{

    public class Item

    {

        public int ItemID { get; private set; } // The unique key

        public string Title { get; set; }

        public string Description { get; set; }

        public DateTime AuctionEndDate { get; set; }

        public IList<Bid> Bids { get; set; }

        public void AddBid(Member member, Decimal amount)

        {

            throw new NotImplementedException();

        }

    }

}

Listing 3-9. Three Test Fixtures

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using Microsoft.VisualStudio.TestTools.UnitTesting;

using MvcPattern.Controllers;

using MvcPattern.Models;

namespace MvcPattern.Tests

{

    [TestClass]

    public class AdminControllerTest

    {

        [TestMethod]

        public void CanAddBid()

        {

            // Arrange - set up the scenario

            Item target = new Item();

            Member member = new Member();

            Decimal amount = 150M;

            // Act - perform the test

            target.AddBid(member, amount);

            // Assert - check the behavior

            Assert.AreEqual(, target.Bids.Count());

            Assert.AreEqual(amount, target.Bids[].BidAmount);

        }

        [TestMethod()]

        [ExpectedException(typeof(InvalidOperationException))]

        public void CannotAddLowerBid()

        {

            // Arrange

            Item target = new Item();

            Member member = new Member();

            Decimal amountParam = 150M;

            // Act

            target.AddBid(member, amountParam);

            target.AddBid(member, amountParam - );

        }

        [TestMethod()]

        public void CanAddHigherBid()

        {

            // Arrange

            Item target = new Item();

            Member firstMember = new Member();

            Member secondMember = new Member();

            Decimal amount = 150M;

            // Act

            target.AddBid(firstMember, amount);

            target.AddBid(secondMember, amount + );

            // Assert

            Assert.AreEqual(, target.Bids.Count());

            Assert.AreEqual(amount + , target.Bids[].BidAmount);

        }

    }

}

Listing 3-10. Implementing the AddBid Method

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

namespace MvcPattern.Models

{

    public class Item

    {

        public int ItemID { get; private set; } // The unique key

        public string Title { get; set; }

        public string Description { get; set; }

        public DateTime AuctionEndDate { get; set; }

        public IList<Bid> Bids { get; set; }

        public Item()

        {

            Bids = new List<Bid>();

        }

        public void AddBid(Member member, Decimal amount)

        {

            Bids.Add(new Bid() {

                BidAmount = amount,

                DatePlaced = DateTime.Now,

                Member = member

            });

        }

    }

}

Listing 3-11. Improving the Implementation of the AddBid Method

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

namespace MvcPattern.Models

{

    public class Item

    {

        public int ItemID { get; private set; } // The unique key

        public string Title { get; set; }

        public string Description { get; set; }

        public DateTime AuctionEndDate { get; set; }

        public IList<Bid> Bids { get; set; }

        public Item()

        {

            Bids = new List<Bid>();

        }

        public void AddBid(Member member, Decimal amount)

        {

            if (Bids.Count ==  || amount > Bids.Max(e => e.BidAmount))

            {

                Bids.Add(new Bid()

                {

                    BidAmount = amount,

                    DatePlaced = DateTime.Now,

                    Member = member

                });

            }

            else

            {

                throw new InvalidOperationException("Bid amount too low");

            }

        }

    }

}