# Testing Strategy

Testing approach for the as4-411 directory and resolver. Ensures determinism, protocol correctness, integration, and resilience.

## Property-based tests for determinism

- **Invariant:** Same normalized request + same store state ⇒ same ordered list of directives (see [resolution-algorithm](resolution-algorithm.md) and [ADR-002](../adr/002-resolution-scoring-determinism.md)).
- Use property-based testing (e.g. fast-check, Hypothesis) to generate many (request, store snapshot) pairs and assert that repeated resolution runs produce identical outputs. Vary identifiers, tenant, constraints, and store contents within valid ranges.
- Tie-break and scoring must be deterministic; tests should catch any dependence on iteration order or non-deterministic randomness.

## Golden test vectors per rail

- Each rail (or protocol adapter) should have **golden test vectors** derived from the [\_rail-template](../protocols/_rail-template.md) “Sample payloads and test vectors” section.
- Tests: given a fixed request and a small, fixed store (or artifact set), the resolver output must match the golden directive list (primary + alternates, protocol, address, evidence). Update goldens only when the spec or algorithm intentionally changes; review changes.

## Integration harness

- **Stack:** Postgres (migrations applied) + resolver service + sample gateway client (or mock that calls resolve and validates response shape).
- **Scenarios:** Create participants, identifiers, endpoints, and routing artifacts via Admin API or store; call resolve with various identifiers and constraints; assert directives and resolution_trace. Include multi-tenant isolation: data for tenant A must not appear in resolve for tenant B.
- Run in CI; use container or test DB so that migrations and seed data are reproducible.

## Chaos tests for connectors

- **Timeouts and retries:** Simulate connector backends (SMP, file, GTT) that delay or fail. Assert timeout and retry behavior per [ADR-005](../adr/005-connector-trust-and-caching.md) and [connectors](connectors.md).
- **Circuit-breaker:** After N failures, connector should open circuit and (per policy) fall back to cache-only or fail closed. Tests should verify circuit state and that no unbounded retries occur.
- **Fallback to cache:** When external source is unavailable, resolver should use cached data only within max stale window; tests assert no stale data beyond that and correct resolution_trace (e.g. “SMP cache” when SMP is down).