# Golden `.sientia` fixtures

Binary conformance vectors for `laborious/utils/bundle/`. They are **bytes the producer's own code
emitted**, not bytes this repository knows how to write: there is no production writer here (change
`import-model-workflow`, design D1). If the producer's layout moves, the reader's tests fail against
these files instead of failing in production.

| File | What it is |
|---|---|
| `golden_model_v3.sientia` | `format_version` 1 bundle, 110767 bytes, plaintext zip 110569 bytes — **two chunks**, so `MESSAGE`/`FINAL` framing is exercised by the golden fixture itself |
| `golden_model_v3.metadata.json` | the `metadata.json` that went into that bundle, in plaintext, so a test can assert the recovered value without decrypting first |
| `regenerate.py` | the script that produced them, importing the producer's `bundle.py`/`crypto.py` by path |

## Password

```
Import1Model!Fixture
```

Recorded deliberately: the fixture protects nothing. It satisfies the producer's export-side
strength rule (≥ 12 characters, upper, lower, digit, symbol), which is checked by
`crypto.validate_password_strength` at generation time.

## Provenance

- Producer repository: `sientia-projects-templates`
- Producer commit: `8d3c1fd117c697e8b352c34f11c732809a4a129b`
  (`8d3c1fd QTZPOC-7: adapt to lint rules picked up from merging main`)
- Producer modules used: `app/src/operations/model_export/bundle.py`,
  `app/src/operations/model_export/crypto.py` — loaded by path, so every constant, the `struct`
  layout, the zip layout, the KDF parameters and the chunk framing come from the producer and none of
  them is re-implemented here
- Producer pin honoured: `pynacl==1.5.0` (this repository pins the same version)

One deviation from task 0.3, recorded rather than hidden: the bytes were generated with the
producer's **code** under *this* repository's venv, not inside the producer's own venv, because that
venv has neither `pynacl` nor `mlflow` installed. The dependency that matters for the bytes is
`pynacl`, pinned identically on both sides, and `mlflow` is not reached — `regenerate.py` builds the
artifact tree itself instead of calling `client.download_artifacts`.

## Contents of the bundle

```
metadata.json                          (written first, no indent, by bundle.build_zip)
artifacts/prediction_model/MLmodel
artifacts/prediction_model/model.pkl            (90 KiB of incompressible filler)
artifacts/prediction_model/conda.yaml
artifacts/prediction_model/python_env.yaml
artifacts/prediction_model/requirements.txt
artifacts/data_model/MLmodel
artifacts/data_model/model.pkl                  (8 KiB)
artifacts/data_model/conda.yaml
artifacts/data_model/python_env.yaml
artifacts/data_model/requirements.txt
artifacts/model_card/model_card.json
artifacts/train_data.csv
artifacts/test_data.csv
artifacts/raw_data.csv
```

No directory entries are stored — the producer only adds paths for which `is_file()` is true.

`parameters` carries `target_variable: "SE"`, which gate 6 requires and which becomes
`model_config.target` in the MongoDB model document.

## Digest boundary — the reason this fixture exists

The header's `ciphertext_digest` is `sha256(file[164:])`: the producer computes
`hashlib.sha256(ciphertext)` over the joined chunks and only then writes
`header + stream_header + ciphertext`, so the 24-byte `secretstream` header is **not** covered.
Verified against this fixture and against a freshly produced bundle. Earlier prose (this change's own
first draft, and `aig-docs/03-sientia-bundle-format.md`) said "everything after the plaintext
header", i.e. from offset 140 — that is wrong, and `tests/laborious/utils/bundle/test_format.py`
asserts both directions so it cannot come back.

## Regenerating

```bash
source ./venv/bin/activate
PRODUCER_REPO=../sientia-projects-templates python tests/fixtures/bundle/regenerate.py
```

Two fields change on every run and are expected to: the 16-byte salt (`os.urandom`) and
`metadata.metadata.export_timestamp` (`datetime.now(UTC)`). Everything else is deterministic —
the filler bytes come from a seeded PRNG. After regenerating, update the producer commit above and
the byte counts in the table.