Adding tests and refactoring handler

CleanArchitecture.sln

@@ -15,6 +15,11 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "CleanArchitecture.Web", "sr
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "CleanArchitecture.Tests", "tests\CleanArchitecture.Tests\CleanArchitecture.Tests.csproj", "{AEE17BAB-D187-4BC5-B640-40CC0749566C}"
 EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution Items", "{250F283E-FE2F-4BBD-9E63-A2265B84E23F}"
+	ProjectSection(SolutionItems) = preProject
+		azure-pipelines.yml = azure-pipelines.yml
+	EndProjectSection
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU

src/CleanArchitecture.Core/Services/ToDoItemService.cs → src/CleanArchitecture.Core/Handlers/ItemCompletedEmailNotificationHandler.cs

@@ -4,7 +4,7 @@ using CleanArchitecture.Core.Interfaces;
 
 namespace CleanArchitecture.Core.Services
 {
-    public class ToDoItemService : IHandle<ToDoItemCompletedEvent>
+    public class ItemCompletedEmailNotificationHandler : IHandle<ToDoItemCompletedEvent>
     {
         public void Handle(ToDoItemCompletedEvent domainEvent)
         {

src/CleanArchitecture.Core/Services/SomeDomainService.cs

+namespace CleanArchitecture.Core.Services
+{
+    public class SomeDomainService
+    {
+        // TODO: This would handle operations involving multiple aggregates or entities
+    }
+}

tests/CleanArchitecture.Tests/Core/Handlers/ItemCompletedEmailNotificationHandlerHandle.cs

+using CleanArchitecture.Core.Entities;
+using CleanArchitecture.Core.Events;
+using CleanArchitecture.Core.Services;
+using System;
+using Xunit;
+
+namespace CleanArchitecture.Tests.Core.Entities
+{
+    public class ItemCompletedEmailNotificationHandlerHandle
+    {
+        [Fact]
+        public void ThrowsExceptionGivenNullEventArgument()
+        {
+            var handler = new ItemCompletedEmailNotificationHandler();
+
+            Exception ex = Assert.Throws<ArgumentNullException>(() => handler.Handle(null));
+        }
+
+        [Fact]
+        public void DoesNothingGivenEventInstance()
+        {
+            var handler = new ItemCompletedEmailNotificationHandler();
+
+            handler.Handle(new ToDoItemCompletedEvent(new ToDoItem()));
+        }
+    }
+}