Added unittests for ViewServiceContainer class

MessageCommunicator.TestGui.Tests/MessageCommunicator.TestGui.Tests.csproj

@@ -0,0 +1,23 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netcoreapp3.1</TargetFramework>
+    <LangVersion>8.0</LangVersion>
+    <Nullable>enable</Nullable>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="FakeItEasy" Version="6.2.1" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.7.1" />
+    <PackageReference Include="MSTest.TestAdapter" Version="2.1.0" />
+    <PackageReference Include="MSTest.TestFramework" Version="2.1.0" />
+    <PackageReference Include="coverlet.collector" Version="1.2.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\MessageCommunicator\MessageCommunicator.csproj" />
+    <ProjectReference Include="..\MessageCommunicator.TestGui\MessageCommunicator.TestGui.csproj" />
+  </ItemGroup>
+
+</Project>

MessageCommunicator.TestGui.Tests/ViewServiceContainerTests.cs

@@ -0,0 +1,98 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reactive.Disposables;
+using System.Text;
+using Avalonia.Controls;
+using FakeItEasy;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace MessageCommunicator.TestGui.Tests
+{
+    [TestClass]
+    public class ViewServiceContainerTests
+    {
+        [TestMethod]
+        public void Check_EmptyObject()
+        {
+            var fakeOwner = A.Fake<IControl>();
+            var viewServiceContainer = new ViewServiceContainer(fakeOwner);
+
+            Assert.IsFalse(viewServiceContainer.IsObserving);
+        }
+
+        [TestMethod]
+        public void Check_RegisterNullViewModel()
+        {
+            var fakeOwner = A.Fake<IControl>();
+            var viewServiceContainer = new ViewServiceContainer(fakeOwner);
+
+            var compositeDisposable = new CompositeDisposable();
+            viewServiceContainer.StartObserving(compositeDisposable, null);
+
+            Assert.IsTrue(compositeDisposable.Count == 1);
+            Assert.IsTrue(viewServiceContainer.IsObserving);
+        }
+
+        [TestMethod]
+        public void Check_RegisterNullViewModel_WithDeregister()
+        {
+            var fakeOwner = A.Fake<IControl>();
+            var viewServiceContainer = new ViewServiceContainer(fakeOwner);
+
+            var compositeDisposable = new CompositeDisposable();
+            viewServiceContainer.StartObserving(compositeDisposable, null);
+
+            compositeDisposable.Dispose();
+
+            Assert.IsTrue(compositeDisposable.Count == 0);
+            Assert.IsFalse(viewServiceContainer.IsObserving);
+        }
+
+        [TestMethod]
+        public void Check_RegisterNullViewModel_WithViewService()
+        {
+            var fakeOwner = A.Fake<IControl>();
+            var viewServiceContainer = new ViewServiceContainer(fakeOwner);
+            var fakeViewService1 = A.Fake<IViewService>();
+            var fakeViewService2 = A.Fake<IViewService>();
+
+            viewServiceContainer.ViewServices.Add(fakeViewService1);
+
+            var compositeDisposable = new CompositeDisposable();
+            viewServiceContainer.StartObserving(compositeDisposable, null);
+
+            viewServiceContainer.ViewServices.Add(fakeViewService2);
+
+            Assert.IsTrue(compositeDisposable.Count == 1);
+            Assert.IsTrue(viewServiceContainer.IsObserving);
+            Assert.IsTrue(Fake.GetCalls(fakeViewService1).Any(actCall => actCall.Method.Name == $"add_{nameof(IViewService.ViewServiceRequest)}"));
+            Assert.IsTrue(Fake.GetCalls(fakeViewService2).Any(actCall => actCall.Method.Name == $"add_{nameof(IViewService.ViewServiceRequest)}"));
+        }
+
+        [TestMethod]
+        public void Check_RegisterNullViewModel__WithDeregister_WithViewService()
+        {
+            var fakeOwner = A.Fake<IControl>();
+            var viewServiceContainer = new ViewServiceContainer(fakeOwner);
+            var fakeViewService1 = A.Fake<IViewService>();
+            var fakeViewService2 = A.Fake<IViewService>();
+
+            viewServiceContainer.ViewServices.Add(fakeViewService1);
+
+            var compositeDisposable = new CompositeDisposable();
+            viewServiceContainer.StartObserving(compositeDisposable, null);
+
+            viewServiceContainer.ViewServices.Add(fakeViewService2);
+
+            compositeDisposable.Dispose();
+
+            Assert.IsTrue(compositeDisposable.Count == 0);
+            Assert.IsFalse(viewServiceContainer.IsObserving);
+            Assert.IsTrue(Fake.GetCalls(fakeViewService1).Any(actCall => actCall.Method.Name == $"add_{nameof(IViewService.ViewServiceRequest)}"));
+            Assert.IsTrue(Fake.GetCalls(fakeViewService1).Any(actCall => actCall.Method.Name == $"remove_{nameof(IViewService.ViewServiceRequest)}"));
+            Assert.IsTrue(Fake.GetCalls(fakeViewService2).Any(actCall => actCall.Method.Name == $"add_{nameof(IViewService.ViewServiceRequest)}"));
+            Assert.IsTrue(Fake.GetCalls(fakeViewService2).Any(actCall => actCall.Method.Name == $"remove_{nameof(IViewService.ViewServiceRequest)}"));
+        }
+    }
+}

MessageCommunicator.TestGui/_Util/_View/ViewServiceContainer.cs

@@ -27,14 +27,16 @@ public ViewServiceContainer(IControl owner)
 
         public void StartObserving(CompositeDisposable disposables, OwnViewModelBase? viewModel)
         {
-            if (viewModel == null) { return; }
             if (_observerDisposable != null)
             {
                 throw new InvalidOperationException("This instance is already registered on the view!");
             }
 
             _observedViewModel = viewModel;
-            _observedViewModel.ViewServiceRequest += this.OnViewServiceRequest;
+            if (_observedViewModel != null)
+            {
+                _observedViewModel.ViewServiceRequest += this.OnViewServiceRequest;
+            }
 
             _observerDisposable = new ObserverStopAdapter(this);
             disposables.Add(_observerDisposable);
@@ -61,7 +63,7 @@ private void StopObserving()
             }
         }
 
-        private object? FindViewService(Type viewServiceType)
+        public object? FindViewService(Type viewServiceType)
         {
             var actParent = (IControl?)this.Owner;
             object? result = null;
@@ -89,17 +91,23 @@ private void OnViewServices_CollectionChanged(object sender, NotifyCollectionCha
         {
             if (_observerDisposable == null) { return; }
 
-            foreach (IViewService? actNewItem in e.NewItems)
+            if (e.NewItems != null)
             {
-                if(actNewItem == null){ continue; }
+                foreach (IViewService? actNewItem in e.NewItems)
+                {
+                    if(actNewItem == null){ continue; }
 
-                actNewItem.ViewServiceRequest += this.OnViewServiceRequest;
+                    actNewItem.ViewServiceRequest += this.OnViewServiceRequest;
+                }
             }
-            foreach (IViewService? actOldItem in e.OldItems)
+            if (e.OldItems != null)
             {
-                if(actOldItem == null){ continue; }
+                foreach (IViewService? actOldItem in e.OldItems)
+                {
+                    if(actOldItem == null){ continue; }
 
-                actOldItem.ViewServiceRequest -= this.OnViewServiceRequest;
+                    actOldItem.ViewServiceRequest -= this.OnViewServiceRequest;
+                }
             }
         }
 

MessageCommunicator.sln

@@ -43,6 +43,8 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Nuget", "Nuget", "{C55F0A61
 		_Misc\Nuget\MessageCommunicator_128.png = _Misc\Nuget\MessageCommunicator_128.png
 	EndProjectSection
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "MessageCommunicator.TestGui.Tests", "MessageCommunicator.TestGui.Tests\MessageCommunicator.TestGui.Tests.csproj", "{890F521E-B731-44C1-9C73-D2E45B5FC2E7}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -65,6 +67,10 @@ Global
 		{7B36AA01-E6A4-49BD-9063-DA56DD25DBAD}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{7B36AA01-E6A4-49BD-9063-DA56DD25DBAD}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{7B36AA01-E6A4-49BD-9063-DA56DD25DBAD}.Release|Any CPU.Build.0 = Release|Any CPU
+		{890F521E-B731-44C1-9C73-D2E45B5FC2E7}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{890F521E-B731-44C1-9C73-D2E45B5FC2E7}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{890F521E-B731-44C1-9C73-D2E45B5FC2E7}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{890F521E-B731-44C1-9C73-D2E45B5FC2E7}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE