[adimoldovan]

Trac ticket: https://core.trac.wordpress.org/ticket/66392

media-new-client-side-upload.test.js deleted all media and all posts after each test, so it had to run in the serial project. In parallel, that cleanup would delete other workers' content. Three of its tests also read the newest attachment on the site, which in parallel can come from another spec.

The new attachments fixture deletes only the attachments that a test uploads or tracks, when the test ends, also when the test fails:

import { test, expect } from '../fixtures';

test( 'example', async ( { attachments } ) => {
	// Upload through REST.
	const media = await attachments.upload( '/absolute/path/to/image.jpg' );

	// Or record an attachment that the browser uploaded, by the id
	// from the upload response.
	attachments.track( 123 );
} );

The spec now records each attachment that its page uploads, through REST or async-upload.php. It reads each attachment by that id, not the newest one, and creates its post with postFactory. The spec moves to parallel.

The README documents attachments and adds a rule: a fixture goes in fixtures/ only when 2 or more spec files use it. Two more client-side upload specs will use attachments in a follow-up PR.

Testing Instructions

1. Run npm run env:cli -- post list --post_type=attachment --format=count and note the number.
2. Run npm run test:e2e -- media-new-client-side-upload. All 18 tests pass.
3. Repeat step 1. The number is the same.
4. Run npm run test:e2e -- --project=parallel --shuffle --repeat-each=2. Every run of media-new-client-side-upload.test.js passes.

Use of AI Tools

AI assistance: Yes
Tool(s): Claude Code
Model(s): Claude Opus 5.5
Used for: Code change, test runs and this description.

---

This Pull Request is for code review only. Please keep all other discussion in the Trac ticket. Do not merge this Pull Request. See GitHub Pull Requests for Code Review in the Core Handbook for more details.

[Copilot]

🟡 Changes recommended

The upload test can leave persisted attachments uncleaned when metadata generation returns HTTP 500 because it does not capture the attachment ID header before checking response success.

1 open issue

• Track attachment IDs from headers before upload response processing · New

What changed in this PR

This PR moves the Add New Media client-side upload spec into the parallel E2E project by replacing site-wide cleanup and newest-attachment queries with test-owned data tracking.

Changes:

• Adds an attachment fixture for uploads, tracking, and scoped cleanup.
• Updates the spec to query attachments by ID and create its parent post through postFactory.
• Enables parallel execution and documents attachment usage and shared-fixture placement.

File	Description
tests/​e2e/​specs/​media-new-client-side-upload.test.js	Tracks browser uploads and uses test-owned attachments and posts.
tests/​e2e/​README.md	Documents the attachment fixture and shared-fixture placement rule.
tests/​e2e/​playwright.config.js	Removes the spec from the serial-only list.
tests/​e2e/​fixtures/​index.js	Registers the attachment fixture.
tests/​e2e/​fixtures/​attachment.js	Adds attachment upload, tracking, and teardown cleanup.

_{Review effort: Balanced}

[Copilot]

🟡 Changes recommended

The REST upload path can leak an attachment when metadata generation fails because it does not track the attachment ID from the response header before uploadMedia() rejects, leaving teardown unable to delete it.

1 open issue

• Track upload attachment ID before metadata parsing or error propagation · New

1 resolved since last review

• Track attachment IDs from headers before upload response processing

_{Review effort: Balanced}

[Copilot]

🟢 Approval recommended

No active review issues were identified for the changes that isolate media-upload test data for parallel execution.

No open issues 🎉

1 resolved since last review

• Track upload attachment ID before metadata parsing or error propagation

_{Review effort: Balanced}

[github-actions]

The following accounts have interacted with this PR and/or linked issues. I will continue to update these lists as activity occurs.

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Props adrianmoldovanwp.

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[lancewillett]

The scoped cleanup and attachment-ID reads make these existing tests suitable for parallel execution without deleting another worker’s media or selecting its latest upload.

The synchronous X-WP-Upload-Attachment-ID tracking also addresses the two cleanup misses: an HTTP error after attachment creation and teardown before response-body parsing completes. Focused Playwright diagnostics passed for both, plus the upload helper’s success/error paths. These were controlled local diagnostics, not a full local WordPress E2E run.

All four E2E CI jobs and JavaScript type checking passed on this revision. No blocking findings remain.

_{AI review · gpt-6}

[lancewillett]

PR #15896 landed in https://core.trac.wordpress.org/changeset/65402