test: 7 calculator-read EPC fields must round-trip 🟥

community heating fuel + CHP fraction, alt-wall is_sheltered, wall
insulation thermal conductivity, pv_diverter_present, measured cylinder
volume, AP50 air permeability — all calculator-read, all silently dropped on
save. FE columns now live; assert deep-equal round-trip and drop their
coverage-guard allow-list entries so the guard enforces reconstruction.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tests/repositories/epc/test_epc_persistence_field_coverage.py

@@ -62,17 +62,6 @@ _UNPERSISTED_ALLOWLIST: dict[str, str] = {
     "SapRoomInRoof.gable_2_height_m": "FE child table pending — room-in-roof detail",
     "SapRoomInRoof.gable_2_length_m": "FE child table pending — room-in-roof detail",
     "SapRoomInRoofSurface": "FE child table pending — room-in-roof surface detail",
-    # --- Nested gaps surfaced by the recursive guard (pre-existing; this guard
-    # only just became able to see them). The calculator READS these, so they are
-    # scoring-relevant silent-drop gaps awaiting FE columns — tracked follow-up,
-    # docs/migrations/epc-property-round-trip-fidelity.md §"recursive-guard gaps".
-    "MainHeatingDetail.community_heating_boiler_fuel_type": "calc-read; no FE column — tracked follow-up",
-    "MainHeatingDetail.community_heating_chp_fraction": "calc-read; no FE column — tracked follow-up",
-    "SapAlternativeWall.is_sheltered": "calc-read; no FE column — tracked follow-up",
-    "SapBuildingPart.wall_insulation_thermal_conductivity": "calc-read; no FE column — tracked follow-up",
-    "SapEnergySource.pv_diverter_present": "calc-read; no FE column — tracked follow-up",
-    "SapHeating.cylinder_volume_measured_l": "calc-read; no FE column — tracked follow-up",
-    "SapVentilation.air_permeability_ap50_m3_h_m2": "calc-read; no FE column — tracked follow-up",
     # --- Nested gaps the calculator does NOT read (dormant); no FE column.
     "SapAlternativeWall.is_basement": "dormant — not read by the calculator; no FE column",
     "SapBuildingPart.floor_u_value": "dormant — not read by the calculator (column exists, unread)",

tests/repositories/epc/test_epc_round_trip.py

@@ -124,6 +124,54 @@ def test_photovoltaic_arrays_round_trip(db_engine: Engine) -> None:
     assert reloaded == original
 
 
+def test_calculator_read_fields_round_trip(db_engine: Engine) -> None:
+    # Seven fields the SAP calculator reads (cert_to_inputs / heat_transmission)
+    # that had no DB column, so they were silently dropped on save (persist !=
+    # score). FE columns now exist; inject all seven onto a clean fixture and
+    # prove they survive the round-trip deep-equal.
+    from dataclasses import replace
+
+    # Arrange
+    original = _load_epc("RdSAP-Schema-21.0.1")
+    bp0 = original.sap_building_parts[0]
+    assert bp0.sap_alternative_wall_1 is not None, "fixture must carry an alt wall"
+    bp0 = replace(
+        bp0,
+        sap_alternative_wall_1=replace(bp0.sap_alternative_wall_1, is_sheltered=True),
+        wall_insulation_thermal_conductivity=35,  # Union[int,str] → JSONB int
+    )
+    heating = original.sap_heating
+    mh0 = replace(
+        heating.main_heating_details[0],
+        community_heating_boiler_fuel_type=35,
+        community_heating_chp_fraction=0.35,
+    )
+    heating = replace(
+        heating,
+        main_heating_details=[mh0, *heating.main_heating_details[1:]],
+        cylinder_volume_measured_l=180,
+    )
+    original = replace(
+        original,
+        sap_building_parts=[bp0, *original.sap_building_parts[1:]],
+        sap_heating=heating,
+        sap_energy_source=replace(original.sap_energy_source, pv_diverter_present=True),
+        sap_ventilation=replace(
+            original.sap_ventilation, air_permeability_ap50_m3_h_m2=7.5
+        ),
+    )
+
+    # Act
+    with Session(db_engine) as session:
+        epc_property_id = EpcPostgresRepository(session).save(original)
+        session.commit()
+    with Session(db_engine) as session:
+        reloaded = EpcPostgresRepository(session).get(epc_property_id)
+
+    # Assert — all seven calculator-read fields survive, deep-equal.
+    assert reloaded == original
+
+
 def test_floor_dimension_heat_loss_flags_round_trip(db_engine: Engine) -> None:
     # SAP 10.2 §3.3 — `is_exposed_floor` and `is_above_partially_heated_space`
     # are heat-loss flags on a `SapFloorDimension`: the calculator routes a floor