Adding E2E test

Microsoft.Identity.Web.sln

@@ -172,6 +172,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "daemon-app-msi", "tests\Dev
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Microsoft.Identity.Web.Sidecar", "src\Microsoft.Identity.Web.Sidecar\Microsoft.Identity.Web.Sidecar.csproj", "{55C81F88-0FFA-491C-A1D7-0ACA7212B59C}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Sidecar.Tests", "tests\E2E Tests\Sidecar.Tests\Sidecar.Tests.csproj", "{946E6BED-2A06-4FF4-3E39-22ACEB44A984}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -411,6 +413,10 @@ Global
 		{55C81F88-0FFA-491C-A1D7-0ACA7212B59C}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{55C81F88-0FFA-491C-A1D7-0ACA7212B59C}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{55C81F88-0FFA-491C-A1D7-0ACA7212B59C}.Release|Any CPU.Build.0 = Release|Any CPU
+		{946E6BED-2A06-4FF4-3E39-22ACEB44A984}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{946E6BED-2A06-4FF4-3E39-22ACEB44A984}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{946E6BED-2A06-4FF4-3E39-22ACEB44A984}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{946E6BED-2A06-4FF4-3E39-22ACEB44A984}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -489,6 +495,7 @@ Global
 		{C14780ED-5756-2A09-C6A7-5DDA433D1E86} = {1DDE1AAC-5AE6-4725-94B6-A26C58D3423F}
 		{A8181404-23E0-D38B-454C-D16ECDB18B9F} = {E37CDBC1-18F6-4C06-A3EE-532C9106721F}
 		{55C81F88-0FFA-491C-A1D7-0ACA7212B59C} = {1DDE1AAC-5AE6-4725-94B6-A26C58D3423F}
+		{946E6BED-2A06-4FF4-3E39-22ACEB44A984} = {45B20A78-91F8-4DD2-B9AD-F12D3A93536C}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {104367F1-CE75-4F40-B32F-F14853973187}

src/Microsoft.Identity.Web.Sidecar/Microsoft.Identity.Web.Sidecar.csproj

@@ -8,6 +8,7 @@
     <GenerateDocumentationFile>False</GenerateDocumentationFile>
     <IsPackable>false</IsPackable>
     <EnablePackageValidation>false</EnablePackageValidation>
+    <NoWarn>$(NoWarn); RS0016</NoWarn>
   </PropertyGroup>
 
   <PropertyGroup>

src/Microsoft.Identity.Web.Sidecar/Program.cs

@@ -1,5 +1,6 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
+#pragma warning disable RS0016 // Public API
 
 using System.Diagnostics;
 using Microsoft.AspNetCore.Authentication.JwtBearer;
@@ -48,3 +49,7 @@
 app.AddValidateRequestEndpoints();
 
 app.Run();
+
+
+// Added for test project WebApplicationFactory discovery
+public partial class Program { }

tests/E2E Tests/Sidecar.Tests/Sidecar.Tests.csproj

@@ -0,0 +1,22 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFrameworks>net9.0</TargetFrameworks>
+    <IsPackable>false</IsPackable>
+    <RootNamespace>Sidecar.Tests</RootNamespace>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <NoWarn>$(NoWarn); CS1591;RS0037</NoWarn>
+    <AssemblyOriginatorKeyFile>../../../build/MSAL.snk</AssemblyOriginatorKeyFile>
+
+  </PropertyGroup>
+  <ItemGroup>
+    <PackageReference Include="Microsoft.AspNetCore.Mvc.Testing" Version="9.0.0" />
+    <PackageReference Include="xunit" Version="2.9.0" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.11.1" />
+    <PackageReference Include="coverlet.collector" Version="6.0.0" />
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\src\Microsoft.Identity.Web.Sidecar\Microsoft.Identity.Web.Sidecar.csproj" />
+  </ItemGroup>
+</Project>

tests/E2E Tests/Sidecar.Tests/ValidateEndpointTests.cs

@@ -0,0 +1,44 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using System.Net.Http.Headers;
+using System.Security.Claims;
+using System.Text;
+using System.Text.Encodings.Web;
+using Microsoft.AspNetCore.Authentication;
+using Microsoft.AspNetCore.Authentication.JwtBearer;
+using Microsoft.AspNetCore.Mvc.Testing;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+using Xunit;
+
+namespace Sidecar.Tests;
+
+public class SidecarApiFactory : WebApplicationFactory<Program>
+{
+    protected override void ConfigureWebHost(Microsoft.AspNetCore.Hosting.IWebHostBuilder builder)
+    {
+        builder.ConfigureServices(services =>
+        {
+        });
+    }
+}
+
+public class ValidateEndpointTests : IClassFixture<SidecarApiFactory>
+{
+    private readonly SidecarApiFactory _factory;
+
+    public ValidateEndpointTests(SidecarApiFactory factory) => _factory = factory;
+
+    [Fact]
+    public async Task Validate_WhenBadTokenAsync()
+    {
+        var client = _factory.CreateClient();
+        client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", "dummy-token");
+        var response = await client.GetAsync("/Validate");
+        Assert.Equal(System.Net.HttpStatusCode.Unauthorized, response.StatusCode);
+        var content = await response.Content.ReadAsStringAsync();
+        Assert.Contains("invalid_token", response.Headers.WwwAuthenticate.ToString(), StringComparison.CurrentCultureIgnoreCase);
+    }
+}