[Chore] Run VRT per variant

[weronikaolejniczak]

Summary

Several issues after having merged #9594...

Lack of mobile snapshots

Turns out playwright.config.ts isn't picked up by the test-runner and is essentially dead code but what's more curious is there's conditional logic for the viewport in the test runner. Not sure what I was thinking at the time.

Added an iteration through "variants". Called them generically because although it's only viewport for now, we may extend it (dark mode, high contrast mode etc.).

skip-vrt flag doesn't re-trigger eui-deploy-docs

The result is that when you add skip-vrt to labels, the CI doesn't trigger the failed eui-deploy-docs again.

No add commit on failed VRT step

If the VRT step fails, we do not add chore(eui): add VRT baseline screenshots, we fold the new snapshots under chore(eui): update VRT baseline screenshots which is better because it doesn't unnecessarily cause another CI run. BUT! The wiki for VRT might be confusing. If the VRT step failed, someone might still expect the add commit when they've added a new story.

[TBD] Still a couple of flakes

I think some of the flakes like EuiPopover Playground might be caused by font subpixel positioning and there's a Chromium flag to disable it: --disable-font-subpixel-positioning.

QA instructions for reviewer

• VRT is ran both for desktop and mobile
• Wiki is clear
• VRT baselines for mobile are added

[Copilot]

Pull request overview

This PR updates EUI’s Storybook visual regression test runner to snapshot each story across multiple “variants” (currently desktop + mobile viewports), and documents how variant baselines are named and how to opt out per-story.

Changes:

• Run VRT screenshots in a loop over defined variants (desktop/mobile) and suffix baseline names with the variant (e.g. …-desktop.png, …-mobile.png).
• Remove packages/eui/playwright.config.ts, which is not used by the current test-storybook-based VRT runner.
• Expand the VRT wiki docs with variant behavior and parameters.vrt.skipVariants.

Reviewed changes

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

File	Description
wiki/contributing-to-eui/testing/visual-regression-testing.md	Documents variant baselines and how to skip variants per story
packages/eui/playwright.config.ts	Removes unused Playwright config file
packages/eui/.storybook/test-runner.ts	Implements per-variant viewport iteration and per-variant snapshot IDs

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[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: 78e9cab

History

• 💚 Build #6759 succeeded 50ad0b4
• 💚 Build #6753 succeeded f3b7ea9
• 💚 Build #6750 succeeded 7e1b833

cc @weronikaolejniczak

[elasticmachine]

💔 Build Failed

• Buildkite Build
• Commit: 78e9cab

Failed CI Steps

• 📷 Test visual regression

History

• 💔 Build #3843 failed 50ad0b4

cc @weronikaolejniczak