进一步探索订单和注册的有界上下文。“我明白，如果一个人想看些新鲜的东西，旅行并不是没有意义的。”儒勒·凡尔纳，环游世界80天

var ordersummary = repository.Query<OrderSummary>().Where(LINQ query to retrieve order summary);
var orderdetails = repository.Query<OrderDetails>().Where(LINQ query to retrieve order details);

var ordersummary = dao.FindAllSummarizedOrders(userId);
var orderdetails = dao.GetOrderDetails(orderId);

var ordersummary = OrderSummaryDAO.FindAll(userId);
var orderdetails = OrderDetailsDAO.Get(orderId);

不要期望代码示例与参考实现中的代码完全匹配。本章描述了CQRS过程中的一个步骤，但是随着我们了解更多并重构代码，实现可能会发生变化。

public string AccessCode { get; set; }protected Order()
{...this.AccessCode = HandleGenerator.Generate(5);
}

[HttpPost]
public ActionResult Find(string email, string accessCode)
{var orderId = orderDao.LocateOrder(email, accessCode);if (!orderId.HasValue){return RedirectToAction("Find", new { conferenceCode = this.ConferenceCode });}return RedirectToAction("Display", new { conferenceCode = this.ConferenceCode, orderId = orderId.Value });
}

public DateTime? ReservationExpirationDate { get; private set; }public void MarkAsReserved(DateTime expirationDate, IEnumerable<SeatQuantity> seats)
{...this.ReservationExpirationDate = expirationDate;this.Items.Clear();this.Items.AddRange(seats.Select(seat => new OrderItem(seat.SeatType, seat.Quantity)));
}

public void Handle(SeatsReserved message)
{if (this.State == ProcessState.AwaitingReservationConfirmation){var expirationTime = this.ReservationAutoExpiration.Value;this.State = ProcessState.ReservationConfirmationReceived;if (this.ExpirationCommandId == Guid.Empty){var bufferTime = TimeSpan.FromMinutes(5);var expirationCommand = new ExpireRegistrationProcess { ProcessId = this.Id };this.ExpirationCommandId = expirationCommand.Id;this.AddCommand(new Envelope<ICommand>(expirationCommand){Delay = expirationTime.Subtract(DateTime.UtcNow).Add(bufferTime),});}this.AddCommand(new MarkSeatsAsReserved{OrderId = this.OrderId,Seats = message.ReservationDetails.ToList(),Expiration = expirationTime,});}...
}

[HttpGet]
public ActionResult SpecifyRegistrantDetails(string conferenceCode, Guid orderId)
{var repo = this.repositoryFactory();using (repo as IDisposable){var draftOrder = repo.Find<DraftOrder>(orderId);var conference = repo.Query<Conference>().Where(c => c.Code == conferenceCode).FirstOrDefault();this.ViewBag.ConferenceName = conference.Name;this.ViewBag.ConferenceCode = conference.Code;this.ViewBag.ExpirationDateUTCMilliseconds = draftOrder.BookingExpirationDate.HasValue ? ((draftOrder.BookingExpirationDate.Value.Ticks - EpochTicks) / 10000L) : 0L;this.ViewBag.OrderId = orderId;return View(new AssignRegistrantDetails { OrderId = orderId });}
}

using System;
using System.ComponentModel.DataAnnotations;
using Common;public class AssignRegistrantDetails : ICommand
{public AssignRegistrantDetails(){this.Id = Guid.NewGuid();}public Guid Id { get; private set; }public Guid OrderId { get; set; }[Required(AllowEmptyStrings = false)]public string FirstName { get; set; }[Required(AllowEmptyStrings = false)]public string LastName { get; set; }[Required(AllowEmptyStrings = false)]public string Email { get; set; }
}

@model Registration.Commands.AssignRegistrantDetails...<div class="editor-label">@Html.LabelFor(model => model.FirstName)</div><div class="editor-field">@Html.EditorFor(model => model.FirstName)</div>
<div class="editor-label">@Html.LabelFor(model => model.LastName)</div><div class="editor-field">@Html.EditorFor(model => model.LastName)</div>
<div class="editor-label">@Html.LabelFor(model => model.Email)</div><div class="editor-field">@Html.EditorFor(model => model.Email)</div>

<appSettings>...<add key="ClientValidationEnabled" value="true" /><add key="UnobtrusiveJavaScriptEnabled" value="true" />
</appSettings>

[HttpPost]
public ActionResult SpecifyRegistrantDetails(string conferenceCode, Guid orderId, AssignRegistrantDetails command)
{if (!ModelState.IsValid){return SpecifyRegistrantDetails(conferenceCode, orderId);}this.commandBus.Send(command);return RedirectToAction("SpecifyPaymentDetails", new { conferenceCode = conferenceCode, orderId = orderId });
}

public class OrderViewModelGenerator :IEventHandler<OrderPlaced>, IEventHandler<OrderUpdated>,IEventHandler<OrderPartiallyReserved>, IEventHandler<OrderReservationCompleted>,IEventHandler<OrderRegistrantAssigned>
{private readonly Func<ConferenceRegistrationDbContext> contextFactory;public OrderViewModelGenerator(Func<ConferenceRegistrationDbContext> contextFactory){this.contextFactory = contextFactory;}public void Handle(OrderPlaced @event){using (var context = this.contextFactory.Invoke()){var dto = new DraftOrder(@event.SourceId, DraftOrder.States.Created){AccessCode = @event.AccessCode,};dto.Lines.AddRange(@event.Seats.Select(seat => new DraftOrderItem(seat.SeatType, seat.Quantity)));context.Save(dto);}}public void Handle(OrderRegistrantAssigned @event){...}public void Handle(OrderUpdated @event){...}public void Handle(OrderPartiallyReserved @event){...}public void Handle(OrderReservationCompleted @event){...}...
}

public class ConferenceRegistrationDbContext : DbContext
{...public T Find<T>(Guid id) where T : class{return this.Set<T>().Find(id);}public IQueryable<T> Query<T>() where T : class{return this.Set<T>();}public void Save<T>(T entity) where T : class{var entry = this.Entry(entity);if (entry.State == System.Data.EntityState.Detached)this.Set<T>().Add(entity);this.SaveChanges();}
}

public class ConferenceDao : IConferenceDao
{private readonly Func<ConferenceRegistrationDbContext> contextFactory;public ConferenceDao(Func<ConferenceRegistrationDbContext> contextFactory){this.contextFactory = contextFactory;}public ConferenceDetails GetConferenceDetails(string conferenceCode){using (var context = this.contextFactory.Invoke()){return context.Query<Conference>().Where(dto => dto.Code == conferenceCode).Select(x => new ConferenceDetails { Id = x.Id, Code = x.Code, Name = x.Name, Description = x.Description, StartDate = x.StartDate }).FirstOrDefault();}}public ConferenceAlias GetConferenceAlias(string conferenceCode){...}public IList<SeatType> GetPublishedSeatTypes(Guid conferenceId){...}
}

Feature:  Conference configuration scenarios for creating and editing Conference settingsIn order to create or update a Conference configurationAs a Business CustomerI want to be able to create or update a Conference and set its propertiesBackground: 
Given the Business Customer selected the Create Conference optionScenario: An existing unpublished Conference is selected and published
Given this conference information
| Owner         | Email                    | Name      | Description                             | Slug   | Start      | End        |
| William Flash | william@fabrikam.com | CQRS2012P | CQRS summit 2012 conference (Published) | random | 05/02/2012 | 05/12/2012 |
And the Business Customer proceeds to create the Conference
When the Business Customer proceeds to publish the Conference
Then the state of the Conference changes to PublishedScenario: An existing Conference is edited and updated
Given an existing published conference with this information
| Owner         | Email                    | Name      | Description                            | Slug   | Start      | End        |
| William Flash | william@fabrikam.com | CQRS2012U | CQRS summit 2012 conference (Original) | random | 05/02/2012 | 05/12/2012 |
And the Business Customer proceeds to edit the existing settings with this information
| Description                           |
| CQRS summit 2012 conference (Updated) |
When the Business Customer proceeds to save the changes
Then this information appears in the Conference settings
| Description                           |
| CQRS summit 2012 conference (Updated) |...

public class ConferenceConfigurationSteps : StepDefinition
{...[Given(@"the Business Customer proceeds to edit the existing settings with this information")]public void GivenTheBusinessCustomerProceedToEditTheExistingSettignsWithThisInformation(Table table){Browser.Click(Constants.UI.EditConferenceId);PopulateConferenceInformation(table);}[Given(@"an existing published conference with this information")]public void GivenAnExistingPublishedConferenceWithThisInformation(Table table){ExistingConferenceWithThisInformation(table, true);}private void ExistingConferenceWithThisInformation(Table table, bool publish){NavigateToCreateConferenceOption();PopulateConferenceInformation(table, true);CreateTheConference();if(publish) PublishTheConference();ScenarioContext.Current.Set(table.Rows[0]["Email"], Constants.EmailSessionKey);ScenarioContext.Current.Set(Browser.FindText(Slug.FindBy), Constants.AccessCodeSessionKey);}...[When(@"the Business Customer proceeds to save the changes")]public void WhenTheBusinessCustomerProceedToSaveTheChanges(){Browser.Click(Constants.UI.UpdateConferenceId);}...[Then(@"this information appears in the Conference settings")]public void ThenThisInformationIsShowUpInTheConferenceSettings(Table table){Assert.True(Browser.SafeContainsText(table.Rows[0][0]),string.Format("The following text was not found on the page: {0}", table.Rows[0][0]));}private void PublishTheConference(){Browser.Click(Constants.UI.PublishConferenceId);}private void CreateTheConference(){ScenarioContext.Current.Browser().Click(Constants.UI.CreateConferenceId);}private void NavigateToCreateConferenceOption(){// Navigate to Registration pageBrowser.GoTo(Constants.ConferenceManagementCreatePage);}private void PopulateConferenceInformation(Table table, bool create = false){var row = table.Rows[0];if (create){Browser.SetInput("OwnerName", row["Owner"]);Browser.SetInput("OwnerEmail", row["Email"]);Browser.SetInput("name", row["Email"], "ConfirmEmail");Browser.SetInput("Slug", Slug.CreateNew().Value);}Browser.SetInput("Tagline", Constants.UI.TagLine);Browser.SetInput("Location", Constants.UI.Location);Browser.SetInput("TwitterSearch", Constants.UI.TwitterSearch);if (row.ContainsKey("Name")) Browser.SetInput("Name", row["Name"]);if (row.ContainsKey("Description")) Browser.SetInput("Description", row["Description"]);if (row.ContainsKey("Start")) Browser.SetInput("StartDate", row["Start"]);if (row.ContainsKey("End")) Browser.SetInput("EndDate", row["End"]);}
}

Scenario: End to end Registration implemented using controllersGiven the Registrant proceeds to make the ReservationAnd these Order Items should be reserved| seat type                 | quantity || General admission         | 1        || Additional cocktail party | 1        |And these Order Items should not be reserved| seat type     || CQRS Workshop |And the Registrant enters these details| first name | last name | email address            || William    | Flash     | william@fabrikam.com |And the Registrant proceeds to Checkout:PaymentWhen the Registrant proceeds to confirm the paymentThen the Order should be created with the following Order Items| seat type                 | quantity || General admission         | 1        || Additional cocktail party | 1        |And the Registrant assigns these seats| seat type                 | first name | last name | email address       || General admission         | William    | Flash     | William@fabrikam.com   || Additional cocktail party | Jim        | Corbin   | Jim@litwareinc.com     |And these seats are assigned| seat type                 | quantity || General admission         | 1        || Additional cocktail party | 1        |

[Given(@"the Registrant proceeds to make the Reservation")]
public void GivenTheRegistrantProceedToMakeTheReservation()
{var redirect = registrationController.StartRegistration(registration, registrationController.ViewBag.OrderVersion) as RedirectToRouteResult;Assert.NotNull(redirect);// Perform external redirectionvar timeout =  DateTime.Now.Add(Constants.UI.WaitTimeout);while (DateTime.Now < timeout && registrationViewModel == null){//ReservationUnknownvar result = registrationController.SpecifyRegistrantAndPaymentDetails((Guid)redirect.RouteValues["orderId"], registrationController.ViewBag.OrderVersion);Assert.IsNotType<RedirectToRouteResult>(result);registrationViewModel = RegistrationHelper.GetModel<RegistrationViewModel>(result);}Assert.False(registrationViewModel == null, "Could not make the reservation and get the RegistrationViewModel");
}...[When(@"the Registrant proceeds to confirm the payment")]
public void WhenTheRegistrantProceedToConfirmThePayment()
{using (var paymentController = RegistrationHelper.GetPaymentController()){paymentController.ThirdPartyProcessorPaymentAccepted(conferenceInfo.Slug, (Guid) routeValues["paymentId"], " ");}
}...[Then(@"the Order should be created with the following Order Items")]
public void ThenTheOrderShouldBeCreatedWithTheFollowingOrderItems(Table table)
{draftOrder = RegistrationHelper.GetModel<DraftOrder>(registrationController.ThankYou(registrationViewModel.Order.OrderId));Assert.NotNull(draftOrder);foreach (var row in table.Rows){var orderItem = draftOrder.Lines.FirstOrDefault(l => l.SeatType == conferenceInfo.Seats.First(s => s.Description == row["seat type"]).Id);Assert.NotNull(orderItem);Assert.Equal(Int32.Parse(row["quantity"]), orderItem.ReservedSeats);}
}

在这些代码示例中，您可以看到是怎样通过标记把SpecFlow feature文件和测试步骤代码链接起来并传递参数的。

public class given_placed_order
{...private Order sut;public given_placed_order(){this.sut = new Order(OrderId, new[] {new OrderPlaced { ConferenceId = ConferenceId,Seats = new[] { new SeatQuantity(SeatTypeId, 5) },ReservationAutoExpiration = DateTime.UtcNow}});}[Fact]public void when_updating_seats_then_updates_order_with_new_seats(){this.sut.UpdateSeats(new[] { new OrderItem(SeatTypeId, 20) });var @event = (OrderUpdated)sut.Events.Single();Assert.Equal(OrderId, @event.SourceId);Assert.Equal(1, @event.Seats.Count());Assert.Equal(20, @event.Seats.ElementAt(0).Quantity);}...
}

public class given_placed_order
{...private EventSourcingTestHelper<Order> sut;public given_placed_order(){this.sut = new EventSourcingTestHelper<Order>();this.sut.Setup(new OrderCommandHandler(sut.Repository, pricingService.Object));this.sut.Given(new OrderPlaced { SourceId = OrderId,ConferenceId = ConferenceId,Seats = new[] { new SeatQuantity(SeatTypeId, 5) },ReservationAutoExpiration = DateTime.UtcNow});}[Fact]public void when_updating_seats_then_updates_order_with_new_seats(){this.sut.When(new RegisterToConference { ConferenceId = ConferenceId, OrderId = OrderId, Seats = new[] { new SeatQuantity(SeatTypeId, 20) }});var @event = sut.ThenHasSingle<OrderUpdated>();Assert.Equal(OrderId, @event.SourceId);Assert.Equal(1, @event.Seats.Count());Assert.Equal(20, @event.Seats.ElementAt(0).Quantity);}...
}

乔什·埃尔斯特讲述了一个关于痛苦、解脱和学习的故事

备注：在任何结构良好的项目中，测试都是开发人员理解项目的基础。各种命名约定，编码风格，设计方法和使用模式的主题都包含在测试套件中，为集成到代码库提供了一个很好的起点。这也是很好的代码专业性实践，熟能生巧!

Feature: Self Registrant scenarios for making a Reservation for a Conference site with all Order Items initially availableIn order to reserve Seats for a conferenceAs an AttendeeI want to be able to select an Order Item from one or many of the available Order Items and make a ReservationBackground: Given the list of the available Order Items for the CQRS Summit 2012 conference with the slug code SelfRegFull| seat type                 | rate | quota || General admission         | $199 | 100   || CQRS Workshop             | $500 | 100   || Additional cocktail party | $50  | 100   |And the selected Order Items| seat type                 | quantity || General admission         | 1        || CQRS Workshop             | 1        || Additional cocktail party | 1        |Scenario: All the Order Items are available and all get reservedWhen the Registrant proceeds to make the Reservation     Then the Reservation is confirmed for all the selected Order ItemsAnd these Order Items should be reserved| seat type                 || General admission         || CQRS Workshop             || Additional cocktail party |And the total should read $749And the countdown started

[Given(@"the '(.*)' site conference")]
public void GivenAConferenceNamed(string conference)
{...
}

备注：一般来说，一个人在任何时候都只能在脑子里保持四到八个不同的想法。为了说明这一概念，让我们保守地计算一下你需要在短期记忆中同时保持的东西的数量，同时遵循上面的启发:
进程类型+进程状态属性+初始状态(NotStarted) + new()的位置+消息类型+中间路由类类型+ 2 *N^ N命令发出(位置、类型、步骤)+判别规则(逻辑也是数据!) > 8

SendCustomerInvoice? -> .
CustomerInvoiceSent! -> .

SendCustomerInvoice? -> CustomerInvoiceHandler
CustomerInvoiceSent! ->-> CustomerNotificationHandler-> AccountsAgeingViewModelGenerator

SendCustomerInvoice? -> CustomerInvoiceHandler
@Invoice::CustomerInvoiceSent! -> .

SendCustomerInvoice? -> CustomerInvoiceHandler
@Invoice::CustomerInvoiceSent! -> .:InvoiceAged! -> .

SendCustomerInvoice? -> CustomerInvoiceHandler
@Invoice::CustomerInvoiceSent! ->-> InvoiceAgeingProcessRouter::InvoiceAgeingProcess

SendCustomerInvoice? -> CustomerInvoiceHandler
@Invoice::CustomerInvoiceSent! ->-> InvoiceAgegingProcessRouter::InvoiceAgeingProcess*InvoiceAgeingProcess.ProcessState = Unpaid