Testing

Read tests/README.md before adding or moving test fixtures. Test-only config belongs under tests/fixtures/, not root config/.

Where a new guard belongs

A test that records an architectural mistake -- something that must not be repeated, checkable from source -- is a Citadel guard, in tests/citadel/, not another file at tests/ root. It runs in the fast phase, so it costs seconds rather than waiting on an asset build.

Two rules the existing guards follow:

State the reason in a named *_RATIONALE appended to the assertion, so a violation teaches. test_db_boundary.py is the model. Where the reason is already stated canonically -- config/gate.toml [boundary], AGENTS.md, a skill -- cite it instead of restating it.