Provides manual and automated checks, test fixtures, acceptance criteria, and remediation guidance for color contrast. This reference fixes the adoption boundary, failure behavior, and observable evidence while leaving environment-specific limits configurable.
Package status: reference context ready for human review. The contract and test scenarios are complete, but no claim is made that an adopting implementation has passed them.
Decision
For Color contrast, adopt native semantics first, with a documented keyboard and focus contract. Treat the block as a release and regression contract built from representative positive, boundary, denial, failure, and recovery cases. This package is a reference contract: the adopting team must choose numeric limits, providers, jurisdictions, and operational owners from evidence in its own environment.
Scope
- The Color contrast actors, inputs, outputs, states, policy or schema versions, and externally visible outcomes described by this testing block.
- Primary and alternate interfaces, background work, caches, integrations, support paths, and evidence that can exercise the same boundary.
- Adoption-specific configuration, rollout, recovery, and verification responsibilities needed to apply the reference safely.
Outside this block
- Choosing a universal vendor, framework, jurisdiction, numeric threshold, retention period, or service-level objective for every adopter.
- Claiming that packaged scenarios have run against a downstream implementation or that this reference grants legal, security, or accessibility certification.
Contract
- Expose a programmatic name, role, value, state, and relationship wherever the visual interface communicates them.
- Every action is operable by keyboard without a trap, and focus order follows the reading and interaction order.
- Announce asynchronous status or errors without moving focus unexpectedly, and associate recovery guidance with the affected control.
- Preserve content and operation under zoom, text spacing, reflow, forced colors, reduced motion, and platform text scaling where applicable.
- Record fixture version, environment, configuration, observed result, and evidence location for every decision-bearing run.
- Separate product failure, dependency failure, test-infrastructure failure, and inconclusive evidence in reports.
- Measure rendered foreground, background, state, text size, and non-text indicators in every theme; token names are not evidence of contrast.
- Do not use color as the only carrier of status, validation, selection, focus, or required information.
Implementation guidance
- Build the smallest deterministic fixture set that spans risk classes, then add production-derived cases only after privacy-safe review.
- Model Color contrast inputs, outputs, actors, states, invariants, side effects, and evidence before selecting framework or vendor details.
- Store the applicable Color contrast contract or policy version with material state so migrations, replay, and support decisions remain attributable.
- Introduce the path behind controlled rollout, compare expected and observed outcomes, and keep a tested recovery route until adoption evidence is complete.
Failure handling and safeguards
- If semantics or focus cannot be preserved, the interaction does not ship behind visual-only behavior; the defect remains release-blocking.
- Invalid or contradictory Color contrast state is rejected or quarantined; the implementation never guesses a value that broadens authority or duplicates an effect.
- Retries are bounded and use durable identity; after exhaustion, work reaches an inspectable terminal state with an accountable owner.
Verification and operations
- Run the suite twice from a clean state and confirm that ordering, retries, and parallel execution do not change the verdict.
- Monitor Color contrast success, denial, validation failure, dependency failure, retry exhaustion, and recovery by contract version without sensitive payload dimensions.
- Re-run paired positive and negative fixtures after policy, schema, dependency, migration, or boundary changes and preserve the resulting evidence.
Adoption assumptions
- Names and values in the example are a concrete fixture, not universal defaults; adopters replace them through documented evidence and ownership.
- The adopting system can provide authenticated identity, durable operation or record versions, bounded telemetry, and a controlled path for change.
The executable-looking examples in this package are fixtures and acceptance contracts. Run the collection validator to check structure and metadata, then translate and execute the scenarios in the target repository before recording implementation evidence.