Test Layout

Pytest collects the entire tests/ tree. New tests go where their ownership and failure mode are clearest:

• unit/ — fast, deterministic properties and focused pure-function proof;
• integration/ — subprocess, cross-surface, or external-package receipts;
• docs/ — documentation structure, snippets, links, and claims contracts;
• downstream/ — versioned fixture applications consumed by integration runners; and
• root test_*.py modules — established component suites, kept stable until a coherent domain is moved as one reviewed change.

Do not move a file merely to reduce a count. Update path-owning docs, scripts, Make targets, and root calculations with every structural move. Unit tests must not use network or subprocesses; integration tests own explicit timeouts and isolated state. Every lane runs under the normal coverage gate.