[adimoldovan]

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

media-library-client-side-upload.test.js and media-modal-client-side-upload.test.js deleted all media after each test, so they had to run in the serial project. All their uploads also had the same file name, so a test found its tile by a name that other specs' uploads share. In parallel, the cleanup would delete other workers' files, and the tile lookups and the "newest attachment" reads could match another spec's upload.

Each test now:

• gives each upload that can create an attachment a unique file name, so its tile name is unique;
• reads its attachments by the ids that the page's upload responses return in the X-WP-Upload-Attachment-ID header;
• lets the attachments fixture delete only what it uploaded.

The modal spec creates its posts with postFactory and opens them on post.php, so its tests no longer run on post-new.php. Both specs move to parallel.

trackUploads() moves to tests/e2e/utils/media-pipeline.js, so the three client-side upload specs share it. A new uniqueFile() helper gives a test file a unique name:

const file = uniqueFile( TEST_IMAGE_PATH );
await fileInput.setInputFiles( file );
await expect( tile( page, titleOf( file ) ) ).toBeVisible();

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-library-client-side-upload media-modal-client-side-upload. All 24 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 the two specs 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.

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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]

🟢 Approval recommended

No active review issues remain for the changes isolating media-upload E2E tests for parallel execution.

No open issues 🎉

What changed in this PR

Builds on #15896 to make the Media Library grid and media modal upload E2E specs safe to run in parallel on a shared WordPress test site.

Changes:

• Uses unique upload filenames and response-provided attachment IDs to avoid matching other tests’ media.
• Replaces global cleanup with fixture-managed attachments and posts, and opens modal tests on existing posts.
• Shares upload-tracking utilities across all three client-side upload specs and moves the grid and modal specs into the parallel project.

File	Description
tests/​e2e/​utils/​media-pipeline.js	Adds unique-file and title helpers and centralizes upload tracking.
tests/​e2e/​specs/​media-new-client-side-upload.test.js	Uses scoped fixtures, attachment IDs, and shared upload tracking.
tests/​e2e/​specs/​media-modal-client-side-upload.test.js	Isolates uploads and uses fixture-created posts for modal tests.
tests/​e2e/​specs/​media-library-client-side-upload.test.js	Scopes tile lookups, attachment assertions, and cleanup to each test.
tests/​e2e/​README.md	Documents attachment cleanup and shared-fixture placement.
tests/​e2e/​playwright.config.js	Removes client-side upload specs from the serial list.
tests/​e2e/​fixtures/​index.js	Registers the attachments fixture.
tests/​e2e/​fixtures/​attachment.js	Adds per-test attachment tracking and cleanup.

_{Review effort: Balanced}

[github-actions]

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[Copilot]

🟢 Approval recommended

No active review issues remain for the media upload test-isolation changes.

No open issues 🎉

_{Review effort: Balanced}

[lancewillett]

The parallel migration is supported by the existing upload tests: with the proposed parallel configuration held fixed, two workers and three repetitions produced 2 failures/4 passes using the base specs, and 6 passes using this head, without retries. This comparison exercises the migration; it does not indicate a failure under the original serial configuration.

The changes preserve the upload assertions while giving each test its own attachment identity and cleanup. All four E2E CI jobs and type checking passed, and the refreshed Copilot review has no open issues.

_{AI review · gpt-6}

[lancewillett]

PR #15903 landed in https://core.trac.wordpress.org/changeset/65403