Running and extending the open-dj conformance corpus

Phase 16 (OPEN-03c) ships a seed corpus under tests/fixtures/conformance/. Each fixture is a self-contained triple:

• expected.opendj.json -- hand-authored canonical document.
• capabilities.yaml -- per-adapter drop mask (which fields the adapter is legitimately allowed to lose on round-trip).
• optional vendor-DB snapshot under fixtures/ (empty in v0; adapters synthesise from the expected document).

Running the suite

pytest -m conformance

A subset across adapters:

pytest tests/test_conformance.py -k "serato"
pytest tests/test_conformance.py -k "traktor"

Unimplemented adapters (rekordbox, djay in Phase 16 execution; potentially others) emit skip at collection time rather than fail. A green CI run with skips is expected while adapter phases are still in flight.

Fixture format

Each capabilities.yaml looks like:

source: manual                 # or "generated" for auto-built fixtures
applies:
  serato:
    drops: ["rating", "bpm"]   # fields Serato is allowed to lose
  traktor:
    drops: ["bpm"]
  rekordbox:
    drops: ["bpm"]
  djay:
    drops: ["bpm"]

The set of supported drop paths lives in tests/test_conformance.py _mask() -- currently rating, cue_points.color, cue_points.memory, bpm, duration_ms, album, play_count, color_rgb, cues, and identity masks for track_id and file_path.

Adding a fixture

1. Pick the next unused number (04-<slug>).
2. Create expected.opendj.json -- must validate against open-dj/schema/v0.2/open-dj.schema.json.
3. Create capabilities.yaml with a drops list per adapter.
4. Run pytest -m conformance and adjust the mask until it passes for every adapter you expect to support.

Adding an adapter

1. Land apps/adapters/<name>/ implementing the Adapter Protocol in apps/open_dj/schema.py. (The former apps/adapters/_shim/ package was retired in phase 16-15 when apps.open_dj shipped its typed dataclass layer.)
2. Register the adapter in tests/test_conformance.py _load_adapter with a short name.
3. Add a per-adapter entry to the applies: section of every fixture capabilities.yaml describing which fields it legitimately drops.
4. Re-run pytest -m conformance; a passing run proves round-trip.