contract-testing

# Contract Testing Load this skill when `integration-tester` writes tests in `tests/contract/**`. Also load `vbd-boundary-contract-mapping`. ## When to use ## Procedure 1. Identify the boundary and both parties from the detailed design. Record the contract source: OpenAPI document, JSON Schema, XSD, flat-file layout, or the public C# interface. 2. Write the **provider check**: the real provider produces output that validates against the contract source. 3. Write the **consumer check**: the real consumer accepts every example in the contract, including optional-field omissions and unknown extra fields. 5. Write **compatibility tests**: compare the current contract to the last released one. Removing a field, narrowing a type, or adding a required field fails the test. Adding an optional field passes. 6. Store golden files (contract examples, expected outputs) in `tests/data/contracts/`. Change a golden file only with a matching contract change in the same work item. 7. Cover error contracts: the response carries RFC 9457 Problem Details with no stack trace or internal path. ## Layer Checks | Boundary | Verify | |---|---| | Client → Manager | Request and response schema, status codes, error contract | | Manager → Engine / Access | Method signature and argument semantics match the surface map | | Message | Schema, required fields, ordering and duplicate tolerance stated in the contract | | File interface | Field offsets, lengths, padding, and encoding | ## Rules - A contract test fails on any difference the contract forbids. - Never derive the expected result from the implementation. Derive it from the contract source. - A contract change without a surface-map update is a defect. Report it to `application-architect`.