Server test.

Author: ilonatommy

src/Components/test/E2ETest/ServerRenderingTests/NoInteractivityTest.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Net.Http;
 using Components.TestServer.RazorComponents;
 using Microsoft.AspNetCore.Components.E2ETest.Infrastructure;
 using Microsoft.AspNetCore.Components.E2ETest.Infrastructure.ServerFixtures;
@@ -25,6 +26,21 @@ public NoInteractivityTest(
     public override Task InitializeAsync()
         => InitializeAsync(BrowserFixture.StreamingContext);
 
+    [Fact]
+    public async Task CanRenderNotFound()
+    {
+        var url = $"{ServerPathBase}/render-not-found-ssr";
+        Navigate(url);
+        var statusCode = await GetStatusCodeAsync(url);
+        Assert.Equal(404, statusCode);
+    }
+    private async Task<int> GetStatusCodeAsync(string relativeUrl)
+    {
+        using var client = new HttpClient();
+        string absoluteUrl = $"{_serverFixture.RootUri}/{relativeUrl}";
+        var response = await client.GetAsync(absoluteUrl);
+        return (int)response.StatusCode;
+    }
     [Fact]
     public void NavigationManagerCanRefreshSSRPageWhenInteractivityNotPresent()
     {

src/Components/test/testassets/Components.TestServer/RazorComponents/Pages/Rendering/NotFoundSSR.razor

@@ -0,0 +1,11 @@
+@page "/render-not-found-ssr"
+@inject NavigationManager NavigationManager
+
+<p id="test-info">Any content</p>
+
+@code{
+    protected override void OnInitialized()
+    {
+        NavigationManager.NotFound();
+    }
+}

src/Components/test/testassets/Components.TestServer/RazorComponents/Pages/Routing/RoutingTestCases.razor

@@ -23,4 +23,13 @@
     <li>
         <a href="routing/complex-segment(value)">Complex segments</a>
     </li>
+    <li>
+        <a href="routing/not-found-ssr">Not found page for Static Server Rendering</a>
+    </li>
+    <li>
+        <a href="routing/not-found-webassembly">Not found page for Interactive WebAssembly rendering</a>
+    </li>
+    <li>
+        <a href="routing/not-found-server">Not found page for Interactive Server rendering</a>
+    </li>
 </ul>