Refactor read-model event dispatch to reduce Handle method complexity

TransactionProcessor.BusinessLogic.Tests/DomainEventHandlers/ReadModelDomainEventHandlerTests.cs

@@ -1,7 +1,9 @@
+using System;
 using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
 using Moq;
+using Shared.DomainDrivenDesign.EventSourcing;
 using Shared.Logger;
 using Shouldly;
 using SimpleResults;
@@ -15,6 +17,8 @@ namespace TransactionProcessor.BusinessLogic.Tests.DomainEventHandlers;
 
 public class ReadModelDomainEventHandlerTests
 {
+    private sealed record UnhandledDomainEvent() : DomainEvent(Guid.NewGuid(), Guid.NewGuid());
+
     private readonly Mock<ITransactionProcessorReadModelRepository> EstateReportingRepository;
     private readonly ReadModelDomainEventHandler DomainEventHandler;
 
@@ -64,4 +68,15 @@ public async Task ReadModelDomainEventHandler_Handle_StatementGeneratedEvent_Mar
         this.EstateReportingRepository.Verify(r => r.MarkStatementAsGenerated(domainEvent, It.IsAny<CancellationToken>()), Times.Once);
         this.EstateReportingRepository.Verify(r => r.UpdateMerchant(domainEvent, It.IsAny<CancellationToken>()), Times.Never);
     }
+
+    [Fact]
+    public async Task ReadModelDomainEventHandler_Handle_UnhandledDomainEvent_ReturnsSuccessWithoutRepositoryCalls()
+    {
+        UnhandledDomainEvent domainEvent = new();
+
+        Result result = await this.DomainEventHandler.Handle(domainEvent, CancellationToken.None);
+
+        result.IsSuccess.ShouldBeTrue();
+        this.EstateReportingRepository.VerifyNoOtherCalls();
+    }
 }

TransactionProcessor.BusinessLogic/EventHandling/ReadModelDomainEventHandler.cs

@@ -33,18 +33,26 @@ public ReadModelDomainEventHandler(ITransactionProcessorReadModelRepository esta
         }
 
         public Task<Result> Handle(IDomainEvent domainEvent,
-                                   CancellationToken cancellationToken)
+                                   CancellationToken cancellationToken) =>
+            this.TryHandleDomainEvent(domainEvent, cancellationToken, out Task<Result> handledTask)
+                ? handledTask
+                : Task.FromResult(Result.Success());
+
+        private bool TryHandleDomainEvent(IDomainEvent domainEvent,
+                                          CancellationToken cancellationToken,
+                                          out Task<Result> handledTask)
         {
             foreach (Func<IDomainEvent, CancellationToken, Task<Result>> domainEventHandler in this.DomainEventHandlers)
             {
-                Task<Result> task = domainEventHandler(domainEvent, cancellationToken);
-                if (task != null)
+                handledTask = domainEventHandler(domainEvent, cancellationToken);
+                if (handledTask != null)
                 {
-                    return task;
+                    return true;
                 }
             }
 
-            return Task.FromResult(Result.Success());
+            handledTask = null;
+            return false;
         }
 
         private Task<Result> HandleEstateDomainEvent(IDomainEvent domainEvent,