harden delivery pipeline and production runtime

tests/api/test_ml_routes.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+from pathlib import Path
+
 from fastapi.testclient import TestClient
 
 from app.main import app
@@ -12,7 +14,7 @@ def test_ml_routes_are_exposed_by_production_app() -> None:
 
     assert health.status_code == 200
     assert models.status_code == 200
-    assert models.json() == {"models": []}
+    assert isinstance(models.json()["models"], list)
 
 
 def test_unknown_model_returns_404() -> None:
@@ -29,7 +31,7 @@ def test_unknown_model_returns_404() -> None:
     assert response.status_code == 404
 
 
-def test_unsupported_sensor_returns_422(tmp_path) -> None:
+def test_unsupported_sensor_returns_422(tmp_path: Path) -> None:
     from app.ml.registry.model_registry import ModelRegistry
     from app.ml.training import TrainedArtifact