test: add unit tests for ServiceCollectionExtensions

X10D.Tests/X10D.Tests.csproj

@@ -14,6 +14,7 @@
     </PropertyGroup>
 
     <ItemGroup>
+        <PackageReference Include="Microsoft.Extensions.Hosting" Version="7.0.0"/>
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.5.0"/>
         <PackageReference Include="Moq" Version="4.18.4"/>
         <PackageReference Include="MSTest.TestAdapter" Version="3.0.2"/>
@@ -25,6 +26,7 @@
     </ItemGroup>
 
     <ItemGroup>
+        <ProjectReference Include="..\X10D.Hosting\X10D.Hosting.csproj"/>
         <ProjectReference Include="..\X10D\X10D.csproj"/>
     </ItemGroup>
 

X10D.Tests/src/Hosting/ServiceCollectionTests.cs

@@ -0,0 +1,60 @@
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Moq;
+using X10D.Hosting.DependencyInjection;
+
+namespace X10D.Tests.Hosting;
+
+[TestClass]
+public class ServiceCollectionTests
+{
+    [TestMethod]
+    public void AddHostedSingleton_ShouldRegisterServiceAsSingletonAndAsHostedService()
+    {
+        var services = new ServiceCollection();
+
+        services.AddHostedSingleton<TestService>();
+
+        var serviceProvider = services.BuildServiceProvider();
+        var service = serviceProvider.GetService<TestService>();
+        var hostedService = serviceProvider.GetService<IHostedService>();
+
+        Assert.IsNotNull(service);
+        Assert.IsNotNull(hostedService);
+        Assert.IsInstanceOfType(service, typeof(TestService));
+        Assert.IsInstanceOfType(hostedService, typeof(TestService));
+        Assert.AreSame(service, hostedService);
+    }
+
+    [TestMethod]
+    public void AddHostedSingleton_ShouldRegisterServiceTypeAsSingletonAndAsHostedService()
+    {
+        var services = new ServiceCollection();
+
+        services.AddHostedSingleton(typeof(TestService));
+
+        var serviceProvider = services.BuildServiceProvider();
+        var service = serviceProvider.GetService<TestService>();
+        var hostedService = serviceProvider.GetService<IHostedService>();
+
+        Assert.IsNotNull(service);
+        Assert.IsNotNull(hostedService);
+        Assert.IsInstanceOfType(service, typeof(TestService));
+        Assert.IsInstanceOfType(hostedService, typeof(TestService));
+        Assert.AreSame(service, hostedService);
+    }
+
+    private sealed class TestService : IHostedService
+    {
+        public Task StartAsync(CancellationToken cancellationToken)
+        {
+            return Task.CompletedTask;
+        }
+
+        public Task StopAsync(CancellationToken cancellationToken)
+        {
+            return Task.CompletedTask;
+        }
+    }
+}