[test-quarantine] Fix Flaky test: FormsInputDateTest.InputDateInteractsWithEditContext_NullableDateTimeOffset

[NanthiniMahalingam]

Bug Description

• The E2E test InputDateInteractsWithEditContext_NullableDateTimeOffset in FormsInputDateTest.cs is intermittently failing.

Description of code changes

• I have set the native date-input values directly (with ISO-formatted strings) and dispatching the change event, instead of simulating locale-sensitive keystrokes into the browser's native date picker.
• Also updates the BlazorWasmTestAppFixture to use the Gateway:PathBase config key and map the SPA fallback file so the test host serves the app correctly.

Fixes #67243,
Fixes #31734,
Fixes #35018

Output

Before

After

[Copilot]

Pull request overview

This PR addresses intermittent flakiness in the FormsInputDateTest.InputDateInteractsWithEditContext_NullableDateTimeOffset E2E test by avoiding locale- and timing-sensitive SendKeys interactions with native date/time inputs, and improves the WASM test host configuration so the app is served correctly behind the Blazor Gateway.

Changes:

• Replace SendKeys-driven interactions with a JS helper that sets native date/time input values directly (ISO-formatted) and dispatches a change event.
• Enable SPA fallback static web asset generation for BasicTestApp to support correct fallback routing when served via static web assets.
• Update the WASM test app fixture to configure path base using the Gateway:PathBase configuration key.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/Components/test/testassets/BasicTestApp/BasicTestApp.csproj	Enables static web asset SPA fallback generation for the test app.
src/Components/test/E2ETest/Tests/FormsInputDateTest.cs	Switches date/time input interactions to deterministic JS value setting + change dispatch to reduce flakiness.
src/Components/test/E2ETest/Infrastructure/ServerFixtures/BlazorWasmTestAppFixture.cs	Passes path base via Gateway:PathBase so the Blazor Gateway applies it correctly.

[Youssef1313]

Per #35018 (comment), the issue for this test should be only affecting the 8 and 9 release branches, and the test is expected to already be stable on main.

Were you able to reproduce a test failure on main?

@ilonatommy if you can look at this community PR.

[ilonatommy]

Per #35018 (comment), the issue for this test should be only affecting the 8 and 9 release branches, and the test is expected to already be stable on main.

Were you able to reproduce a test failure on main?

@ilonatommy if you can look at this community PR.

Exactly, I think this PR is trying to address to many issues at the same time, without a clear explanation how did they reproduce the failure, what was the hit rate, with unrelated changes already merged in #67903. The mentioned tests are not even quarantined, it's most probably mis-targetted.

[ilonatommy]

Closing in favor of #68107. We don't want to change the nature of the tests, executing JS script is not same as invoking SendKeys by Selenium.