add safe home assistant error handling

tests/api/test_entities.py

@@ -2,6 +2,7 @@ from collections.abc import Sequence
 
 from fastapi.testclient import TestClient
 
+from app.ha.exceptions import HaTimeoutError
 from app.ha.models import HaEntitySummary
 from app.ha.reader import HaReader
 from app.main import app
@@ -15,6 +16,14 @@ class FakeHaReader(HaReader):
         return [HaEntitySummary(entity_id="sensor.temperature", domain="sensor")]
 
 
+class TimeoutHaReader(HaReader):
+    def __init__(self) -> None:
+        pass
+
+    def read_entities(self) -> Sequence[HaEntitySummary]:
+        raise HaTimeoutError("contains internal details that must not leak")
+
+
 def test_openapi_docs_are_available() -> None:
     with TestClient(app) as client:
         response = client.get("/docs")
@@ -44,3 +53,11 @@ def test_entities_returns_503_without_home_assistant_config() -> None:
             delattr(app.state, "ha_reader")
         response = client.get("/v1/entities")
     assert response.status_code == 503
+
+
+def test_entities_maps_ha_errors_without_leaking_details() -> None:
+    with TestClient(app) as client:
+        app.state.ha_reader = TimeoutHaReader()
+        response = client.get("/v1/entities")
+    assert response.status_code == 504
+    assert response.json() == {"detail": "Home Assistant request timed out."}

tests/ha/test_ha_client.py

@@ -0,0 +1,79 @@
+from __future__ import annotations
+
+from unittest.mock import Mock
+
+import pytest
+import requests
+
+from app.ha.client import HaClient, HaClientSettings
+from app.ha.exceptions import (
+    HaAuthError,
+    HaHttpError,
+    HaTimeoutError,
+    HaUnexpectedPayloadError,
+)
+
+
+def _client_with_response(response: Mock) -> HaClient:
+    client = HaClient(HaClientSettings(url="http://ha.local", token="secret-token"))
+    client._session.get = Mock(return_value=response)  # type: ignore[method-assign]
+    return client
+
+
+def _response(status_code: int = 200, payload: object | None = None) -> Mock:
+    response = Mock()
+    response.status_code = status_code
+    response.json.return_value = [] if payload is None else payload
+    if status_code >= 400:
+        response.raise_for_status.side_effect = requests.HTTPError("upstream failed")
+    return response
+
+
+def test_list_entities_returns_home_assistant_payload() -> None:
+    payload = [{"entity_id": "sensor.temperature", "state": "21"}]
+    client = _client_with_response(_response(payload=payload))
+
+    assert client.list_entities() == payload
+
+
+def test_list_entities_maps_timeout() -> None:
+    client = HaClient(HaClientSettings(url="http://ha.local", token="secret-token"))
+    client._session.get = Mock(side_effect=requests.Timeout("secret-token"))  # type: ignore[method-assign]
+
+    with pytest.raises(HaTimeoutError):
+        client.list_entities()
+
+
+@pytest.mark.parametrize("status_code", [401, 403])
+def test_list_entities_maps_auth_errors(status_code: int) -> None:
+    client = _client_with_response(_response(status_code=status_code))
+
+    with pytest.raises(HaAuthError) as exc_info:
+        client.list_entities()
+
+    assert exc_info.value.status_code == status_code
+
+
+def test_list_entities_maps_http_errors() -> None:
+    client = _client_with_response(_response(status_code=500))
+
+    with pytest.raises(HaHttpError) as exc_info:
+        client.list_entities()
+
+    assert exc_info.value.status_code == 500
+
+
+def test_list_entities_rejects_invalid_json() -> None:
+    response = _response()
+    response.json.side_effect = ValueError("not json")
+    client = _client_with_response(response)
+
+    with pytest.raises(HaUnexpectedPayloadError):
+        client.list_entities()
+
+
+def test_list_entities_rejects_non_list_payload() -> None:
+    client = _client_with_response(_response(payload={"entity_id": "sensor.temperature"}))
+
+    with pytest.raises(HaUnexpectedPayloadError):
+        client.list_entities()