M8-R17: allocate thermal standing costs by service

tests/test_energy_expose.py

@@ -3002,6 +3002,11 @@ def test_m8_thermal_today_summary_ends_at_frozen_now(energy_db) -> None:
             "heating": Decimal("0"), "hot_water_heating": Decimal("1.25"),
             "hot_water": Decimal("2.75"), "hot_water_tax": Decimal("9.99"),
         },
+        "fixed_breakdown": {
+            "heating_network": Decimal("0"), "metering": Decimal("0"),
+            "delivery_set": Decimal("0"), "hot_water_network": Decimal("0"),
+            "other": Decimal("0"),
+        },
     }
 
     def summarize_spy(_session: Session, start: datetime, end: datetime, *, now: datetime) -> dict:
@@ -3023,5 +3028,53 @@ def test_m8_thermal_today_summary_ends_at_frozen_now(energy_db) -> None:
             assert entity.value_getter(session) == Decimal("0")
             hot_water_total = next(item.entity for item in build_catalog(session)
                                    if item.entity.key.endswith(".hot_water_total_today"))
-            assert hot_water_total.value_getter(session) == Decimal("4.00")
+            assert hot_water_total.value_getter(session) == Decimal("13.99")
     assert captured["end"] == now
+
+
+@pytest.mark.parametrize("suffix", ("total", "today"))
+def test_m8_thermal_totals_allocate_standing_costs_and_match_all_in(energy_db, suffix: str) -> None:
+    """Heating and hot water each receive their assigned costs, without overlap."""
+    from app.integrations.expose import build_catalog
+    from app.services import timezone as tz
+
+    now = datetime(2026, 1, 15, 10, tzinfo=timezone.utc)
+    summary = {
+        "period_count": 2,
+        "fixed_cost": Decimal("35"),
+        "total_cost": Decimal("54"),
+        "breakdown": {
+            "heating": Decimal("10"), "hot_water_heating": Decimal("2"),
+            "hot_water": Decimal("3"), "hot_water_tax": Decimal("4"),
+        },
+        "fixed_breakdown": {
+            "heating_network": Decimal("5"), "metering": Decimal("6"),
+            "delivery_set": Decimal("7"), "hot_water_network": Decimal("9"),
+            "other": Decimal("8"),
+        },
+    }
+
+    with Session(energy_db) as session:
+        _make_thermal_source_and_meter(session, "heating", now)
+        _make_thermal_source_and_meter(session, "hot_water", now)
+        session.commit()
+        with (
+            patch("app.integrations.expose._utc_now", return_value=now),
+            patch.object(tz, "local_tz", return_value=ZoneInfo("Europe/Amsterdam")),
+            patch.object(tz, "local_now", return_value=now.astimezone(ZoneInfo("Europe/Amsterdam"))),
+            patch("app.services.meter_cost.summarize", return_value=summary),
+        ):
+            entities = {item.entity.key.rsplit(".", 1)[-1]: item.entity
+                        for item in build_catalog(session) if item.entity.key.startswith("thermal_cost.")}
+            heating = entities[f"heating_{suffix}"].value_getter(session)
+            hot_water = entities[f"hot_water_total_{suffix}"].value_getter(session)
+
+            assert heating == Decimal("36")  # 10 + heating_network + metering + delivery_set + other
+            assert hot_water == Decimal("18")  # 2 + 3 + 4 + hot_water_network
+            assert entities[f"fixed_{suffix}"].value_getter(session) == Decimal("35")
+            assert entities[f"all_in_{suffix}"].value_getter(session) == Decimal("54")
+            assert heating + hot_water == entities[f"all_in_{suffix}"].value_getter(session)
+            # Component entities deliberately remain variable-only.
+            assert entities[f"hot_water_heating_{suffix}"].value_getter(session) == Decimal("2")
+            assert entities[f"water_{suffix}"].value_getter(session) == Decimal("3")
+            assert entities[f"water_tax_{suffix}"].value_getter(session) == Decimal("4")