Document WCAG 2.2 AA compliance evidence for Blindeforbundet sign-off
epic-screen-reader-support-complex-widgets-task-018 — Produce the final WCAG 2.2 AA compliance documentation package required for Blindeforbundet acceptance sign-off. Include: WCAGComplianceChecker CI reports showing zero critical violations, manual VoiceOver and TalkBack test results for all five epic components, a mapping of each WCAG 2.2 AA criterion to the implementing component, and a summary of known limitations or deferred items with mitigation plans.
Acceptance Criteria
Technical Requirements
Execution Context
Tier 4 - 323 tasks
Can start after Tier 3 completes
Implementation Notes
Use a structured Markdown template with clearly labelled sections to ensure nothing is omitted. Store the template in docs/compliance/wcag-2.2-aa-evidence-template.md and fill it in as a new versioned file per release. For the WCAG 2.2 AA criterion mapping, start from the official W3C criterion list (50 criteria at Levels A and AA) — do not rely on memory. For each criterion, the mapping should link to the specific Flutter Semantics API or component that implements it: e.g., SC 1.1.1 → Image.semanticLabel, SC 2.1.1 → Semantics(onTap:), SC 4.1.2 → Semantics(label:, button: true).
For manual VoiceOver tests, use an iPhone running the latest iOS with VoiceOver enabled via Settings > Accessibility. For TalkBack, use a physical Android device or a well-configured emulator (API 31+). Document exact gesture sequences used (swipe right to next element, double-tap to activate) so tests are reproducible. Blindeforbundet is the primary accessibility stakeholder per the workshop summary — they have VoiceOver/JAWS expertise and will scrutinize screen reader behaviour specifically.
Frame the document language for a non-developer audience while including technical evidence as appendices.
Testing Requirements
This is a documentation task; the primary validation is a peer review checklist rather than automated tests. Checklist items: (1) All 50 WCAG 2.2 AA criteria are present in the criterion mapping table with no gaps. (2) Every manual test result cell is filled — no blanks or 'TBD'. (3) CI report artifact SHA matches the latest green CI run on main.
(4) Known limitations section is present even if empty (explicitly state 'No known limitations'). (5) Document passes a spell-check and grammar review. (6) Two team members independently verify the CI evidence section before submission. Additionally, run the WCAGComplianceChecker one final time against the release build (not debug) and attach that report as an appendix.
Flutter does not natively enforce a focus trap within a bottom sheet or modal dialog in the semantic tree — VoiceOver and TalkBack can navigate outside the sheet to background content. Implementing a reliable focus trap requires overriding the semantic tree, which may conflict with the existing modal helper infrastructure in the app and require changes to shared components beyond this feature's scope.
Mitigation & Contingency
Mitigation: Prototype the focus trap on the first modal sheet implementation before building the remaining sheets. Evaluate Flutter's ExcludeSemantics and BlockSemantics widgets as the trap mechanism, and coordinate with the team owning the shared modal helpers to agree on a non-breaking integration point before writing production code.
Contingency: If a complete semantic focus trap cannot be implemented without breaking existing modal patterns, implement a partial solution using FocusScope with autofocus on the modal's first element and a prominent 'Return to main content' semantic action, documenting the deviation from WCAG 2.4.3 with a scheduled remediation item.
The activity wizard uses BLoC state management and the UI rebuilds the entire step widget subtree on transition. If the semantic tree is traversed by VoiceOver before the build cycle settles, focus may land on a stale or partially rendered step, causing the wrong step label or progress value to be announced. This is particularly problematic for blind users who cannot visually verify the announcement against the screen.
Mitigation & Contingency
Mitigation: Coordinate ActivityWizardStepSemantics with FocusManagementService (from the core services epic) to delay focus placement until the post-build callback confirms the new step's semantic tree is complete. Write integration tests using the AccessibilityTestHarness that assert the full announcement sequence across all five wizard steps.
Contingency: If post-build focus delay is insufficient due to async BLoC emission timing, add an explicit semantic notification barrier in the wizard cubit that emits a 'step ready' event only after the new widget tree has been marked as built, decoupling the announcement trigger from the raw state transition.
Automated WCAG contrast ratio checking on widget tree snapshots may produce false positives for gradient backgrounds, dark-mode overrides, or design token overrides that are resolved at runtime but appear as unresolvable colours at static analysis time. Excessive false positives would erode team trust in the CI gate, leading to suppression rules that also mask real violations.
Mitigation & Contingency
Mitigation: Scope the WCAGComplianceChecker to check only solid-colour backgrounds in the first iteration, explicitly excluding gradients from contrast checks with documented rationale. Design the check output to distinguish 'undetermined' (gradient/unknown) from 'fail' (solid colour below threshold) so the team can take targeted action on genuine failures only.
Contingency: If false positive rates exceed 20% of reported violations during initial CI runs, switch the CI gate from a hard build failure to a warning annotation on the pull request, combined with a mandatory manual review step, until the checker's rule set has been tuned to match actual design token values.