trixie-api/docs/contract-testing.md

Contract Testing

Fixtures cover HTTP responses, authenticated WebSocket events, errors, permissions, version negotiation, reconnects, and server-owned state transitions. Fixtures are deterministic, synthetic, and secret-free. Every new contract must include at least one valid fixture and a negative case where validation rules are important.

The current realtime envelope is deliberately transport-neutral: the server may deliver it over an authenticated WebSocket or a future compatible transport, but the event identity and payload rules remain the same. event_id is the stable deduplication key for at-least-once delivery.