Added example Saga implementation

oskardudycz · Sep 3, 2024 · 4f57da6 · 4f57da6
1 parent 7dc4043
commit 4f57da6
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Showing 32 changed files with 1,894 additions and 128 deletions.
diff --git a/Workshops/EventDrivenArchitecture/02-EntitiesDefinition/Core/EventBus.cs b/Workshops/EventDrivenArchitecture/02-EntitiesDefinition/Core/EventBus.cs
@@ -9,12 +9,12 @@ public ValueTask Publish(object[] events, CancellationToken _)
     {
         foreach (var @event in events)
         {
-            if (!eventHandlers.TryGetValue(@event.GetType(), out var handlers))
-                continue;
-
             foreach (var middleware in middlewares)
                 middleware(@event);
 
+            if (!eventHandlers.TryGetValue(@event.GetType(), out var handlers))
+                continue;
+
             foreach (var handler in handlers)
                 handler(@event);
         }

diff --git a/Workshops/EventDrivenArchitecture/03-BusinessProcesses/Core/CommandBus.cs b/Workshops/EventDrivenArchitecture/03-BusinessProcesses/Core/CommandBus.cs
@@ -5,7 +5,7 @@ namespace BusinessProcesses.Core;
 
 public class CommandBus
 {
-    public ValueTask Send(object[] commands, CancellationToken _)
+    public async ValueTask Send(object[] commands, CancellationToken ct)
     {
         foreach (var command in commands)
         {
@@ -15,20 +15,18 @@ public ValueTask Send(object[] commands, CancellationToken _)
             foreach (var middleware in middlewares)
                 middleware(command);
 
-            handler(command);
+            await handler(command, ct);
         }
-
-        return ValueTask.CompletedTask;
     }
 
-    public void Handle<T>(Action<T> eventHandler)
+    public void Handle<T>(Func<T, CancellationToken, ValueTask> eventHandler)
     {
-        commandHandlers[typeof(T)] = x => eventHandler((T)x);
+        commandHandlers[typeof(T)] = (command, ct) => eventHandler((T)command, ct);
     }
 
     public void Use(Action<object> middleware) =>
         middlewares.Add(middleware);
 
-    private readonly ConcurrentDictionary<Type, Action<object>> commandHandlers = new();
+    private readonly ConcurrentDictionary<Type, Func<object, CancellationToken, ValueTask>> commandHandlers = new();
     private readonly List<Action<object>> middlewares = [];
 }
diff --git a/Workshops/EventDrivenArchitecture/03-BusinessProcesses/Core/EventBus.cs b/Workshops/EventDrivenArchitecture/03-BusinessProcesses/Core/EventBus.cs
@@ -4,7 +4,7 @@ namespace BusinessProcesses.Core;
 
 public class EventBus
 {
-    public ValueTask Publish(object[] events, CancellationToken _)
+    public async ValueTask Publish(object[] events, CancellationToken ct)
     {
         foreach (var @event in events)
         {
@@ -15,15 +15,13 @@ public ValueTask Publish(object[] events, CancellationToken _)
                 middleware(@event);
 
             foreach (var handler in handlers)
-                handler(@event);
+                await handler(@event, ct);
         }
-
-        return ValueTask.CompletedTask;
     }
 
-    public void Subscribe<T>(Action<T> eventHandler)
+    public void Subscribe<T>(Func<T, CancellationToken, ValueTask> eventHandler)
     {
-        Action<object> handler = x => eventHandler((T)x);
+        Func<object, CancellationToken, ValueTask> handler = (@event, ct) => eventHandler((T)@event, ct);
 
         eventHandlers.AddOrUpdate(
             typeof(T),
@@ -39,6 +37,6 @@ public void Subscribe<T>(Action<T> eventHandler)
     public void Use(Action<object> middleware) =>
         middlewares.Add(middleware);
 
-    private readonly ConcurrentDictionary<Type, List<Action<object>>> eventHandlers = new();
+    private readonly ConcurrentDictionary<Type, List<Func<object, CancellationToken, ValueTask>>> eventHandlers = new();
     private readonly List<Action<object>> middlewares = [];
 }
diff --git a/Workshops/EventDrivenArchitecture/03-BusinessProcesses/Core/MessageCatcher.cs b/Workshops/EventDrivenArchitecture/03-BusinessProcesses/Core/MessageCatcher.cs
@@ -2,7 +2,7 @@
 
 namespace BusinessProcesses.Core;
 
-public class EventCatcher
+public class MessageCatcher
 {
     public List<object> Published { get; } = [];
 

diff --git a/.../EventDrivenArchitecture/03-BusinessProcesses/Version1-Aggregates/BusinessProcessTests.cs b/.../EventDrivenArchitecture/03-BusinessProcesses/Version1-Aggregates/BusinessProcessTests.cs
@@ -0,0 +1,224 @@
+using Bogus;
+using BusinessProcesses.Core;
+using BusinessProcesses.Version1_Aggregates.GroupCheckouts;
+using BusinessProcesses.Version1_Aggregates.GuestStayAccounts;
+using Xunit;
+using Xunit.Abstractions;
+using Database = BusinessProcesses.Core.Database;
+
+namespace BusinessProcesses.Version1_Aggregates;
+
+using static GuestStayAccountCommand;
+using static GuestStayAccountEvent;
+using static GroupCheckoutCommand;
+
+public class BusinessProcessTests
+{
+    [Fact]
+    public async Task GroupCheckoutForMultipleGuestStayWithoutPaymentsAndCharges_ShouldComplete()
+    {
+        // Given;
+        Guid[] guestStays = [Guid.NewGuid(), Guid.NewGuid(), Guid.NewGuid()];
+
+        await guestStayFacade.CheckInGuest(new CheckInGuest(guestStays[0], now.AddDays(-1)));
+        await guestStayFacade.CheckInGuest(new CheckInGuest(guestStays[1], now.AddDays(-1)));
+        await guestStayFacade.CheckInGuest(new CheckInGuest(guestStays[2], now.AddDays(-1)));
+        publishedMessages.Reset();
+        // And
+        var groupCheckoutId = Guid.NewGuid();
+        var clerkId = Guid.NewGuid();
+        var command = new InitiateGroupCheckout(groupCheckoutId, clerkId, guestStays, now);
+
+        // When
+        await guestStayFacade.InitiateGroupCheckout(command);
+
+        // Then
+        publishedMessages.ShouldReceiveMessages(
+            [
+                new GroupCheckoutEvent.GroupCheckoutInitiated(groupCheckoutId, clerkId, guestStays, now),
+                new CheckOutGuest(guestStays[0], now, groupCheckoutId),
+                new GuestCheckedOut(guestStays[0], now, groupCheckoutId),
+                new GroupCheckoutEvent.GuestCheckoutCompleted(groupCheckoutId, guestStays[0], now),
+                new CheckOutGuest(guestStays[1], now, groupCheckoutId),
+                new GuestCheckedOut(guestStays[1], now, groupCheckoutId),
+                new GroupCheckoutEvent.GuestCheckoutCompleted(groupCheckoutId, guestStays[1], now),
+                new CheckOutGuest(guestStays[2], now, groupCheckoutId),
+                new GuestCheckedOut(guestStays[2], now, groupCheckoutId),
+                new GroupCheckoutEvent.GuestCheckoutCompleted(groupCheckoutId, guestStays[2], now),
+                new GroupCheckoutEvent.GroupCheckoutCompleted(groupCheckoutId, guestStays, now),
+            ]
+        );
+    }
+
+    [Fact]
+    public async Task GroupCheckoutForMultipleGuestStayWithAllStaysSettled_ShouldComplete()
+    {
+        // Given;
+        Guid[] guestStays = [Guid.NewGuid(), Guid.NewGuid(), Guid.NewGuid()];
+        decimal[] amounts = [generate.Finance.Amount(), generate.Finance.Amount(), generate.Finance.Amount()];
+
+        await guestStayFacade.CheckInGuest(new CheckInGuest(guestStays[0], now.AddDays(-1)));
+        await guestStayFacade.RecordCharge(new RecordCharge(guestStays[0], amounts[0], now.AddHours(-2)));
+        await guestStayFacade.RecordPayment(new RecordPayment(guestStays[0], amounts[0], now.AddHours(-1)));
+
+        await guestStayFacade.CheckInGuest(new CheckInGuest(guestStays[1], now.AddDays(-1)));
+        await guestStayFacade.RecordPayment(new RecordPayment(guestStays[1], amounts[1], now.AddHours(-1)));
+        await guestStayFacade.RecordCharge(new RecordCharge(guestStays[1], amounts[1], now.AddHours(-2)));
+
+        await guestStayFacade.CheckInGuest(new CheckInGuest(guestStays[2], now.AddDays(-1)));
+        await guestStayFacade.RecordCharge(new RecordCharge(guestStays[0], amounts[2], now.AddHours(-2)));
+        await guestStayFacade.RecordPayment(new RecordPayment(guestStays[0], amounts[2] / 2, now.AddHours(-1)));
+        await guestStayFacade.RecordPayment(new RecordPayment(guestStays[0], amounts[2] / 2, now.AddHours(-1)));
+        publishedMessages.Reset();
+        // And
+        var groupCheckoutId = Guid.NewGuid();
+        var clerkId = Guid.NewGuid();
+        var command = new InitiateGroupCheckout(groupCheckoutId, clerkId, guestStays, now);
+
+        // When
+        await guestStayFacade.InitiateGroupCheckout(command);
+
+        // Then
+        publishedMessages.ShouldReceiveMessages(
+            [
+                new GroupCheckoutEvent.GroupCheckoutInitiated(groupCheckoutId, clerkId, guestStays, now),
+                new CheckOutGuest(guestStays[0], now, groupCheckoutId),
+                new GuestCheckedOut(guestStays[0], now, groupCheckoutId),
+                new GroupCheckoutEvent.GuestCheckoutCompleted(groupCheckoutId, guestStays[0], now),
+                new CheckOutGuest(guestStays[1], now, groupCheckoutId),
+                new GuestCheckedOut(guestStays[1], now, groupCheckoutId),
+                new GroupCheckoutEvent.GuestCheckoutCompleted(groupCheckoutId, guestStays[1], now),
+                new CheckOutGuest(guestStays[2], now, groupCheckoutId),
+                new GuestCheckedOut(guestStays[2], now, groupCheckoutId),
+                new GroupCheckoutEvent.GuestCheckoutCompleted(groupCheckoutId, guestStays[2], now),
+                new GroupCheckoutEvent.GroupCheckoutCompleted(groupCheckoutId, guestStays, now),
+            ]
+        );
+    }
+
+    [Fact]
+    public async Task GroupCheckoutForMultipleGuestStayWithOneSettledAndRestUnsettled_ShouldFail()
+    {
+        // Given;
+        Guid[] guestStays = [Guid.NewGuid(), Guid.NewGuid(), Guid.NewGuid()];
+        decimal[] amounts = [generate.Finance.Amount(), generate.Finance.Amount(), generate.Finance.Amount()];
+
+        // 🟢 settled
+        await guestStayFacade.CheckInGuest(new CheckInGuest(guestStays[0], now.AddDays(-1)));
+        await guestStayFacade.RecordCharge(new RecordCharge(guestStays[0], amounts[0], now.AddHours(-2)));
+        await guestStayFacade.RecordPayment(new RecordPayment(guestStays[0], amounts[0], now.AddHours(-1)));
+
+        // 🛑 payment without charge
+        await guestStayFacade.CheckInGuest(new CheckInGuest(guestStays[1], now.AddDays(-1)));
+        await guestStayFacade.RecordPayment(new RecordPayment(guestStays[1], amounts[1], now.AddHours(-1)));
+
+        // 🛑 payment without charge
+        await guestStayFacade.CheckInGuest(new CheckInGuest(guestStays[2], now.AddDays(-1)));
+        await guestStayFacade.RecordCharge(new RecordCharge(guestStays[2], amounts[2], now.AddHours(-2)));
+        await guestStayFacade.RecordPayment(new RecordPayment(guestStays[2], amounts[2] / 2, now.AddHours(-1)));
+        publishedMessages.Reset();
+        // And
+        var groupCheckoutId = Guid.NewGuid();
+        var clerkId = Guid.NewGuid();
+        var command = new InitiateGroupCheckout(groupCheckoutId, clerkId, guestStays, now);
+
+        // When
+        await guestStayFacade.InitiateGroupCheckout(command);
+
+        // Then
+        publishedMessages.ShouldReceiveMessages(
+            [
+                new GroupCheckoutEvent.GroupCheckoutInitiated(groupCheckoutId, clerkId, guestStays, now),
+                new CheckOutGuest(guestStays[0], now, groupCheckoutId),
+                new GuestCheckedOut(guestStays[0], now, groupCheckoutId),
+                new GroupCheckoutEvent.GuestCheckoutCompleted(groupCheckoutId, guestStays[0], now),
+                new CheckOutGuest(guestStays[1], now, groupCheckoutId),
+                new GuestCheckoutFailed(guestStays[1], GuestCheckoutFailed.FailureReason.BalanceNotSettled, now,
+                    groupCheckoutId),
+                new GroupCheckoutEvent.GuestCheckoutFailed(groupCheckoutId, guestStays[1], now),
+                new CheckOutGuest(guestStays[2], now, groupCheckoutId),
+                new GuestCheckoutFailed(guestStays[2], GuestCheckoutFailed.FailureReason.BalanceNotSettled, now,
+                    groupCheckoutId),
+                new GroupCheckoutEvent.GuestCheckoutFailed(groupCheckoutId, guestStays[2], now),
+                new GroupCheckoutEvent.GroupCheckoutFailed(
+                    groupCheckoutId,
+                    [guestStays[0]],
+                    [guestStays[1], guestStays[2]],
+                    now
+                ),
+            ]
+        );
+    }
+
+
+    [Fact]
+    public async Task GroupCheckoutForMultipleGuestStayWithAllUnsettled_ShouldFail()
+    {
+        // Given;
+        Guid[] guestStays = [Guid.NewGuid(), Guid.NewGuid(), Guid.NewGuid()];
+        decimal[] amounts = [generate.Finance.Amount(), generate.Finance.Amount(), generate.Finance.Amount()];
+
+        // 🛑 charge without payment
+        await guestStayFacade.CheckInGuest(new CheckInGuest(guestStays[0], now.AddDays(-1)));
+        await guestStayFacade.RecordCharge(new RecordCharge(guestStays[0], amounts[0], now.AddHours(-2)));
+
+        // 🛑 payment without charge
+        await guestStayFacade.CheckInGuest(new CheckInGuest(guestStays[1], now.AddDays(-1)));
+        await guestStayFacade.RecordPayment(new RecordPayment(guestStays[1], amounts[1], now.AddHours(-1)));
+
+        // 🛑 payment without charge
+        await guestStayFacade.CheckInGuest(new CheckInGuest(guestStays[2], now.AddDays(-1)));
+        await guestStayFacade.RecordCharge(new RecordCharge(guestStays[2], amounts[2], now.AddHours(-2)));
+        await guestStayFacade.RecordPayment(new RecordPayment(guestStays[2], amounts[2] / 2, now.AddHours(-1)));
+        publishedMessages.Reset();
+        // And
+        var groupCheckoutId = Guid.NewGuid();
+        var clerkId = Guid.NewGuid();
+        var command = new InitiateGroupCheckout(groupCheckoutId, clerkId, guestStays, now);
+
+        // When
+        await guestStayFacade.InitiateGroupCheckout(command);
+
+        // Then
+        publishedMessages.ShouldReceiveMessages(
+            [
+                new GroupCheckoutEvent.GroupCheckoutInitiated(groupCheckoutId, clerkId, guestStays, now),
+                new CheckOutGuest(guestStays[0], now, groupCheckoutId),
+                new GuestCheckoutFailed(guestStays[0], GuestCheckoutFailed.FailureReason.BalanceNotSettled, now,
+                    groupCheckoutId),
+                new GroupCheckoutEvent.GuestCheckoutFailed(groupCheckoutId, guestStays[0], now),
+                new CheckOutGuest(guestStays[1], now, groupCheckoutId),
+                new GuestCheckoutFailed(guestStays[1], GuestCheckoutFailed.FailureReason.BalanceNotSettled, now,
+                    groupCheckoutId),
+                new GroupCheckoutEvent.GuestCheckoutFailed(groupCheckoutId, guestStays[1], now),
+                new CheckOutGuest(guestStays[2], now, groupCheckoutId),
+                new GuestCheckoutFailed(guestStays[2], GuestCheckoutFailed.FailureReason.BalanceNotSettled, now,
+                    groupCheckoutId),
+                new GroupCheckoutEvent.GuestCheckoutFailed(groupCheckoutId, guestStays[2], now),
+                new GroupCheckoutEvent.GroupCheckoutFailed(
+                    groupCheckoutId,
+                    [],
+                    [guestStays[0], guestStays[1], guestStays[2]],
+                    now
+                ),
+            ]
+        );
+    }
+
+    private readonly Database database = new();
+    private readonly EventBus eventBus = new();
+    private readonly CommandBus commandBus = new();
+    private readonly MessageCatcher publishedMessages = new();
+    private readonly GuestStayFacade guestStayFacade;
+    private readonly Faker generate = new();
+    private readonly DateTimeOffset now = DateTimeOffset.Now;
+    private readonly ITestOutputHelper testOutputHelper;
+
+    public BusinessProcessTests(ITestOutputHelper testOutputHelper)
+    {
+        this.testOutputHelper = testOutputHelper;
+        guestStayFacade = new GuestStayFacade(database, eventBus);
+
+        eventBus.Use(publishedMessages.Catch);
+    }
+}