FUE-T06: trigger HA discovery republish after meter declare/update

tests/test_api_meters.py

@@ -72,6 +72,24 @@ def _declare_payload(**overrides) -> dict:
 # ---------------------------------------------------------------------------
 
 
+@pytest.fixture(autouse=True)
+def mock_publish_discovery():
+    """Auto-mock publish_discovery for all tests in this module.
+
+    The meters API now calls _trigger_discovery_republish (best-effort) after
+    every successful write.  publish_discovery is lazy-imported inside that
+    helper, so we patch it at its canonical source path
+    (app.services.ha_discovery.publish_discovery).  Tests that need to assert
+    the call receive this fixture explicitly; all others benefit from the
+    isolation it provides (no live MQTT broker required).
+    """
+    with patch(
+        "app.services.ha_discovery.publish_discovery",
+        return_value=None,
+    ) as mock:
+        yield mock
+
+
 @pytest.fixture()
 def meters_client(auth_database):
     """TestClient + SQLAlchemy engine for Meter API tests."""
@@ -660,3 +678,78 @@ def test_patch_started_at_earlier_updates_boundary(meters_client):
         if ended is not None and ended.tzinfo is None:
             ended = ended.replace(tzinfo=UTC)
         assert ended == t1_earlier
+
+
+# ---------------------------------------------------------------------------
+# FUE-T06: HA discovery re-publish triggered after meter writes
+# ---------------------------------------------------------------------------
+
+
+def test_declare_meter_triggers_publish_discovery(meters_client, mock_publish_discovery):
+    """POST /api/energy/meters triggers publish_discovery after successful commit."""
+    client, _ = meters_client
+    _login(client)
+
+    t0 = datetime(2025, 1, 1, 0, 0, 0, tzinfo=UTC)
+    with patch("app.api.routes.api.meters.recompute_range", return_value=0):
+        resp = client.post(
+            "/api/energy/meters",
+            json=_declare_payload(label="Discovery Meter", started_at=t0.isoformat()),
+            headers={"X-CSRF-Token": _CSRF},
+        )
+    assert resp.status_code == 201
+    # publish_discovery must have been called exactly once after the declare.
+    mock_publish_discovery.assert_called_once()
+
+
+def test_patch_meter_triggers_publish_discovery(meters_client, mock_publish_discovery):
+    """PATCH /api/energy/meters/{id} triggers publish_discovery after successful commit."""
+    client, _ = meters_client
+    _login(client)
+
+    t0 = datetime(2025, 1, 1, 0, 0, 0, tzinfo=UTC)
+    with patch("app.api.routes.api.meters.recompute_range", return_value=0):
+        resp = client.post(
+            "/api/energy/meters",
+            json=_declare_payload(label="Original Label", started_at=t0.isoformat()),
+            headers={"X-CSRF-Token": _CSRF},
+        )
+    meter_id = resp.json()["id"]
+    # Reset call count: the POST above also called publish_discovery.
+    mock_publish_discovery.reset_mock()
+
+    resp = client.patch(
+        f"/api/energy/meters/{meter_id}",
+        json={"label": "Renamed Label"},
+        headers={"X-CSRF-Token": _CSRF},
+    )
+    assert resp.status_code == 200
+    # publish_discovery must have been called exactly once after the PATCH.
+    mock_publish_discovery.assert_called_once()
+
+
+def test_declare_meter_succeeds_when_publish_discovery_raises(meters_client):
+    """publish_discovery raising an exception must NOT cause POST declare to return 500.
+
+    The _trigger_discovery_republish helper is best-effort: it swallows all
+    exceptions so that a broken MQTT / discovery layer never breaks the API.
+    """
+    client, _ = meters_client
+    _login(client)
+
+    t0 = datetime(2025, 1, 1, 0, 0, 0, tzinfo=UTC)
+    with (
+        patch("app.api.routes.api.meters.recompute_range", return_value=0),
+        patch(
+            "app.services.ha_discovery.publish_discovery",
+            side_effect=RuntimeError("MQTT broker unreachable"),
+        ),
+    ):
+        resp = client.post(
+            "/api/energy/meters",
+            json=_declare_payload(label="Best Effort Meter", started_at=t0.isoformat()),
+            headers={"X-CSRF-Token": _CSRF},
+        )
+    # The meter must be created successfully despite the discovery failure.
+    assert resp.status_code == 201
+    assert resp.json()["label"] == "Best Effort Meter"