chore(dropzone): test suites

[cdransf]

Description

Adds Phase 6 test coverage for the 2nd-gen <swc-dropzone> component migration. Two new files are introduced:

• test/dropzone.test.ts — 13 Storybook Vitest play-function stories covering the full drag lifecycle, status region transitions, size reflection, drop-effect validation, and dev-mode accessible-name warnings
• test/dropzone.a11y.spec.ts — 6 Playwright ARIA snapshot tests verifying role, accessible name, status region announcements across all four states (default, dragged, filled, filled-and-dragged), keyboard focus behavior, and tab order

Motivation and context

Phase 5 (styling) is complete. These tests close the Phase 6 gate before documentation work begins in Phase 7. They also add an explicit non-regression test for the dragover path always calling event.preventDefault(), and cover the dev-mode warning when no accessible name is provided.

Related issue(s)

• fixes SWC-2150

Screenshots (if appropriate)

N/A — test-only change

Author's checklist

• I have read the CONTRIBUTING and PULL_REQUESTS documents.
• I have reviewed the Accessibility Practices for this feature, see: Aria Practices
• I have added automated tests to cover my changes.
• I have included a well-written changeset if my change needs to be published.
• I have included updated documentation if my change required it.

Reviewer's checklist

• Includes a Github Issue with appropriate flag or Jira ticket number without a link
• Includes thoughtfully written changeset if changes suggested include patch, minor, or major features
• Automated tests cover all use cases and follow best practices for writing
• Validated on all supported browsers
• All VRTs are approved before the author can update Golden Hash

Manual review test cases

• Vitest play functions pass in headless Chromium

  1. Run yarn test --story-path=dropzone (or equivalent)
  2. Confirm all 13 play-function stories in Drop Zone/Tests pass without timeout
  3. Confirm no console warnings appear from non-warning stories

• Playwright ARIA snapshots pass

  1. Run yarn test:a11y targeting the drop-zone stories
  2. Confirm all 6 ARIA snapshot tests pass
  3. Confirm the status region announces correctly in dragged, filled, and filled-and-dragged states

• No regressions in the States story

  1. Open Storybook → Drop Zone → States
  2. Confirm all four variants render with correct visual state (default, dragged, filled, filled-and-dragged)
  3. Confirm the filled state hides the illustrated message

Device review

• Did it pass in Desktop?
• Did it pass in (emulated) Mobile?
• Did it pass in (emulated) iPad?

Accessibility testing checklist

• Keyboard (test-only PR; no interactive behavior changed)

  1. Open Storybook → Drop Zone → Overview
  2. Press Tab once; confirm focus lands on the "Browse files" button, not the swc-dropzone host
  3. Confirm the focus ring is visible on the button
  4. Confirm no focus trap exists (pressing Tab again moves focus past the component)

• Screen reader (covered by Playwright ARIA snapshot tests)

  1. Open Storybook → Drop Zone → States
  2. Navigate to the dragged drop zone; confirm VoiceOver/NVDA announces group "Dragged drop zone" and reads the status region content "File ready to drop"
  3. Navigate to the filled drop zone; confirm the status region announces "File accepted"
  4. Navigate to the filled-and-dragged drop zone; confirm the status region announces "Drop to replace existing file"
  5. Confirm the default drop zone's status region is empty and not announced

[changeset-bot]

⚠️ No Changeset found

Latest commit: 440d0d8

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[github-actions]

📚 Branch Preview Links

• Documentation Site (first-gen)
• Storybook (first-gen)
• Storybook (second-gen)

🔍 First Generation Visual Regression Test Results

When a visual regression test fails (or has previously failed while working on this branch), its results can be found in the following URLs:

• Spectrum | Light | Medium | LTR
• Spectrum | Dark | Large | RTL
• Express | Light | Medium | LTR
• Express | Dark | Large | RTL
• Spectrum-two | Light | Medium | LTR
• Spectrum-two | Dark | Large | RTL
• High Contrast Mode | Medium | LTR

Deployed to Azure Blob Storage: pr-6448

If the changes are expected, update the current_golden_images_cache hash in the circleci config to accept the new images. Instructions are included in that file.
If the changes are unexpected, you can investigate the cause of the differences and update the code accordingly.