Improve enhanced navigation suppression in tests

[ilonatommy]

Suppress enhanced navigation once per test

Enhanced navigation suppression was per page, after navigating away we were falling back to enhanced navigation, regardless of the test settings. It's because we were treating the storage as temporary measure where we were setting the suppression flag and instantly removing it after reading it in blazor start function. For tests that never navigated away (did not re-trigger blazor boot function) it was enough but for other ones, not.

Description

• The enhanced navigation suppression flag has an id of test appended. It's unique per test instance.
• To avoid usage of the same test id by multiple tests, we always try to clean the session storage from it on disposal.
• Consecutive navigations in the test will run with same settings as the first page load.
• This PR fixed order of actions: we should navigate to a page only after the suppression method got called.
• It also enabled tests that got disabled because of issues with enhanced navigation suppression.
• Session storage has to be available if we want to suppress enhanced navigation. If a developer wrote a test that is not navigating to any page and chose to skip the automatic navigation in EnhancedNavigationTestUtil.SuppressEnhancedNavigation, they will get an exception like:

Failed to read the 'sessionStorage' property from 'Window': Access 

SuppressEnhancedNavigation appends to the exception message an instruction how to fix this situation.

• To be able to clean the sessionStorage, we have to have access to it. It's accessible only on loaded pages, so we chose the index page as the secure place for conducting the cleanup. To assure we're at the correct location we're checking for "Hello" h1 tag. Tests that use BasicTestApp did not have that h1 element, this PR adds it. At the same time, this PR is changing expectations of BasicTestApp-based tests - they used to look for h1 that was embedded in <app> element. The search criteria got more precise.

Fixes #60875

[Copilot]

Pull Request Overview

This PR improves enhanced navigation suppression in tests by making it persistent per test instance rather than per page. The changes address issues where enhanced navigation suppression was being lost after navigating away from a page, causing tests to fall back to enhanced navigation unexpectedly.

Key changes:

• Enhanced navigation suppression now uses test-specific IDs to maintain state across navigations
• Automatic cleanup of suppression flags when tests complete to prevent interference between tests
• Re-enabled previously disabled tests that were affected by navigation suppression issues

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
BrowserTestBase.cs	Made DisposeAsync virtual to allow overriding for cleanup
Root.razor	Updated to use test-specific suppression keys and removed immediate cleanup
App.razor	Updated to use test-specific suppression keys and removed immediate cleanup
EnhancedNavigationTestUtil.cs	Added test ID generation, improved error handling, and cleanup functionality
EnhancedNavigationTest.cs	Re-enabled quarantined tests and improved test order/cleanup
ServerTestBase.cs	Added automatic cleanup of navigation suppression on test disposal

[ilonatommy]

Used in the enhanced navigation suppression method to check if session storage has conditions to get cleaned properly (page got loaded).

[ilonatommy]

One more thing to fix - the less frequent failure that happens when using GetElementPositionWithRetry:

 Failed Microsoft.AspNetCore.Components.E2ETests.ServerRenderingTests.EnhancedNavigationTest.EnhancedNavigationScrollBehavesSameAsBrowserOnNavigation(enableStreaming: True, useEnhancedNavigation: True, programmaticNavigation: True) [4 s]
  Error Message:
   System.Exception : Failed to execute script to get position for element 'do-programmatic-navigation' after 3 retries. Debug log: Attempt 1: JavaScriptException - javascript error: Cannot read properties of null (reading 'getBoundingClientRect')
  (Session info: chrome=139.0.7258.66). Attempt 2: JavaScriptException - javascript error: Cannot read properties of null (reading 'getBoundingClientRect')
  (Session info: chrome=139.0.7258.66). Attempt 3: JavaScriptException - javascript error: Cannot read properties of null (reading 'getBoundingClientRect')
  (Session info: chrome=139.0.7258.66). 
  Stack Trace:
     at Microsoft.AspNetCore.Components.E2ETest.WebDriverExtensions.GetElementPositionWithRetry(IWebDriver browser, String elementId, Int32 retryCount, Int32 delayBetweenRetriesMs) in /home/vsts/work/1/s/src/Components/test/E2ETest/Infrastructure/WebDriverExtensions/WebDriverExtensions.cs:line 74
   at Microsoft.AspNetCore.Components.E2ETests.ServerRenderingTests.EnhancedNavigationTest.EnhancedNavigationScrollBehavesSameAsBrowserOnNavigation(Boolean enableStreaming, Boolean useEnhancedNavigation, Boolean programmaticNavigation) in /home/vsts/work/1/s/src/Components/test/E2ETest/ServerRenderingTests/EnhancedNavigationTest.cs:line 707
   at InvokeStub_EnhancedNavigationTest.EnhancedNavigationScrollBehavesSameAsBrowserOnNavigation(Object, Span`1)
   at System.Reflection.MethodBaseInvoker.InvokeWithFewArgs(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)