AI agent skill · by @Archive228

Contract Test

Test the boundary between two systems by the contract, not the implementation. Use for APIs, integrations, and shared interfaces.

Archived 2026-10-23 · Source updated 2026-07-14 · License: MIT. Check the original repository for the latest version.

SKILL.md instructions

# Contract Test
Test what the two sides AGREED on, so either can change internals without breaking the other.
- Assert the **shape**: required fields, types, status codes, error format — not internal logic.
- Cover the contract's edges: missing optional fields, the documented error responses, pagination bounds, versioning.
- For consumers: test against the real contract (recorded/real responses), not a mock you wrote to match your assumptions — that mock drifts and lies.
- One source of truth for the schema; both sides validate against it.
A green unit test with a wrong mock is worse than no test. Pin the contract.