test(e2e): fix flaky idle hydration strategy test

[babu-ch]

The idle test in hydrationStrategies.spec.ts is flaky — the loader's setTimeout(10) can complete before the test asserts isHydrated === false.

Let the test control when the loader starts via window.resolveLoader().

Found while investigating CI failures in #14549.

Summary by CodeRabbit

• Tests
  • Updated e2e test harness to support external triggering of async component loading.
  • Enhanced hydration strategy tests to verify component hydration behavior under controlled loading scenarios.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 744a15d2-1274-4697-9737-88b296e67635

📥 Commits

Reviewing files that changed from the base of the PR and between 7df0edd and d475587.

📒 Files selected for processing (2)

• packages/vue/__tests__/e2e/hydration-strat-idle.html
• packages/vue/__tests__/e2e/hydrationStrategies.spec.ts

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📝 Walkthrough

Walkthrough

The changes introduce an externally callable window.resolveLoader() hook in the hydration idle e2e test that defers async component resolution until explicitly invoked, enabling precise control over component loading timing in tests.

Changes

Cohort / File(s)	Summary
Async Loader Hook packages/vue/__tests__/e2e/hydration-strat-idle.html	Added window.resolveLoader function that wraps the previous setTimeout + component resolution + requestIdleCallback flow, deferring execution until the hook is called.
Test Harness & Invocation packages/vue/__tests__/e2e/hydrationStrategies.spec.ts	Extended window type declaration with resolveLoader: () => void property and added explicit invocation of window.resolveLoader() in the idle test case after verifying initial non-hydrated state.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~5 minutes

Suggested labels

ready to merge, scope:hydration

Poem

🐰 A loader waits upon my call,
No rush, no eager resolve at all,
I hold the reins, I choose when done,
Hydration dances, test by test, one by one!

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change: fixing a flaky e2e test for the idle hydration strategy by introducing explicit control over loader timing.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[github-actions]

Size Report

Bundles

File	Size	Gzip	Brotli
runtime-dom.global.prod.js	105 kB	39.9 kB	35.8 kB
vue.global.prod.js	164 kB	59.9 kB	53.2 kB

Usages

Name	Size	Gzip	Brotli
createApp (CAPI only)	48.3 kB	18.8 kB	17.2 kB
createApp	56.5 kB	21.8 kB	20 kB
createSSRApp	60.7 kB	23.6 kB	21.5 kB
defineCustomElement	62.6 kB	23.8 kB	21.7 kB
overall	71 kB	27.2 kB	24.7 kB

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commit: d475587

[babu-ch]

@edison1105 coud you take a look?