fix: reject unprovenanced ML artifacts

tests/test_ml_artifacts.py

@@ -0,0 +1,58 @@
+import json
+from pathlib import Path
+
+from ml import artifacts
+from scoring import engine
+
+
+REPO_ROOT = Path(__file__).resolve().parents[1]
+
+
+def _valid_artifact():
+    return {
+        "artifact_schema_version": artifacts.ML_ARTIFACT_SCHEMA_VERSION,
+        "score_version": artifacts.SCORE_VERSION,
+        "weights": {key: 1 / len(artifacts.REQUIRED_WEIGHT_KEYS) for key in artifacts.REQUIRED_WEIGHT_KEYS},
+        "provenance": {
+            "validation_method": "purged_expanding_window",
+            "label_horizon_days": 365,
+            "weight_scope": "full_history_fit",
+            "training_date_range": {"start": "2018-02-01", "end": "2025-03-21"},
+            "trained_at": "2026-07-01T00:00:00+00:00",
+        },
+    }
+
+
+def test_pre_purge_repository_artifact_is_rejected_with_actionable_status():
+    artifact_path = REPO_ROOT / "config" / "ml_weights.json"
+    artifact = json.loads(artifact_path.read_text())
+
+    status = artifacts.validate_ml_artifact(artifact)
+
+    assert status["valid"] is False
+    assert status["schema_version"] is None
+    assert "artifact_schema_version" in status["errors"]
+
+
+def test_valid_artifact_requires_schema_score_version_and_purged_provenance():
+    artifact = _valid_artifact()
+
+    status = artifacts.validate_ml_artifact(artifact)
+
+    assert status == {
+        "valid": True,
+        "schema_version": artifacts.ML_ARTIFACT_SCHEMA_VERSION,
+        "score_version": artifacts.SCORE_VERSION,
+        "weight_scope": "full_history_fit",
+        "has_oos_fold_weights": False,
+        "errors": [],
+    }
+
+
+def test_live_scoring_refuses_schema_less_weights(tmp_path, monkeypatch):
+    path = tmp_path / "ml_weights.json"
+    path.write_text(json.dumps({"weights": {"fear_greed": 1.0}}))
+    monkeypatch.setattr(engine, "ML_WEIGHTS_PATH", str(path))
+
+    assert engine.load_ml_weights() == {}
+    assert engine.get_ml_artifact_status()["valid"] is False