Try on CI if tests run with small or big window (toggle bar has problems locally because it runs in a small window).

Author: ilonatommy

src/Components/WebAssembly/testassets/StandaloneApp/Pages/Index.razor

@@ -1,5 +1,5 @@
 @page "/"
 
-<h1>Hello, world!</h1>
+<h1 id="session-storage-anchor">Hello, world!</h1>
 
 Welcome to your new app.

src/Components/test/E2ETest/Infrastructure/ServerTestBase.cs

@@ -5,6 +5,7 @@
 using Microsoft.AspNetCore.Components.E2ETests.ServerRenderingTests;
 using Microsoft.AspNetCore.E2ETesting;
 using OpenQA.Selenium;
+using OpenQA.Selenium.BiDi.Communication;
 using Xunit.Abstractions;
 
 namespace Microsoft.AspNetCore.Components.E2ETest.Infrastructure;
@@ -14,17 +15,20 @@ public abstract class ServerTestBase<TServerFixture>
     IClassFixture<TServerFixture>
     where TServerFixture : ServerFixture
 {
-    public string ServerPathBase => "/subdir";
+    private string _serverPathBase;
+    public string ServerPathBase => _serverPathBase;
 
     protected readonly TServerFixture _serverFixture;
 
     public ServerTestBase(
         BrowserFixture browserFixture,
         TServerFixture serverFixture,
-        ITestOutputHelper output)
+        ITestOutputHelper output,
+        string serverPathBase = "/subdir")
         : base(browserFixture, output)
     {
         _serverFixture = serverFixture;
+        _serverPathBase = serverPathBase;
     }
 
     public void Navigate(string relativeUrl)

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

@@ -104,7 +104,7 @@ private static void NavigateToOrigin<TServerFixture>(ServerTestBase<TServerFixtu
     {
         // Navigate to the test origin to ensure the browser is on the correct state to access sessionStorage
         fixture.Navigate($"{fixture.ServerPathBase}/");
-        fixture.Browser.Equal("Hello", () => fixture.Browser.Exists(By.TagName("h1")).Text);
+        fixture.Browser.Exists(By.Id("session-storage-anchor"));
     }
 
     private static string GrantTestIdCore(IWebDriver browser)

src/Components/test/E2ETest/Tests/StandaloneAppTest.cs

@@ -16,7 +16,7 @@ public StandaloneAppTest(
         BrowserFixture browserFixture,
         BlazorWasmTestAppFixture<StandaloneApp.Program> serverFixture,
         ITestOutputHelper output)
-        : base(browserFixture, serverFixture, output)
+        : base(browserFixture, serverFixture, output, "")
     {
     }
 

src/Components/test/testassets/BasicTestApp/Index.razor

@@ -3,7 +3,7 @@
 @inject NavigationManager NavigationManager
 
 <div id="test-selector">
-    <h1 style="margin: 0; padding: 0; line-height: 1;">Hello</h1>
+    <h1 id="session-storage-anchor" style="margin: 0; padding: 0; line-height: 1;">Hello</h1>
     Select test:
     <select id="test-selector-select" @bind=SelectedComponentTypeName>
         <option value="none">Choose...</option>

src/Components/test/testassets/Components.TestServer/RazorComponents/Pages/Index.razor

@@ -2,6 +2,6 @@
 
 <PageTitle>Home</PageTitle>
 
-<h1>Hello</h1>
+<h1 id="session-storage-anchor">Hello</h1>
 
 <p>This is a Razor Component endpoint.</p>