Integration Contract Testing

Use this skill to prove that adapter boundaries match the contracts the application relies on.

Core Rules

• Test the boundary contract, not the vendor implementation.
• Validate both successful and failed response shapes.
• Keep fixtures realistic, minimal, and sanitized.
• Prefer schema validation at the boundary and assert that invalid vendor data is rejected.
• Use fakes for application tests and focused integration tests for adapter behavior.
• Make CI deterministic. Networked tests need explicit opt-in, stable credentials, and clear skip behavior.

Contract Test Layers

1. Mapping tests: external fixture to internal type.
2. Error normalization tests: vendor failure to application error.
3. Adapter seam tests: adapter sends the expected command/request and handles the response.
4. Optional live smoke: confirms credentials, endpoint, and one safe operation in controlled environments.