Map display EnergyElements on full-SAP certs for the FE panel 🟥

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

datatypes/epc/domain/tests/test_from_sap_schema.py

@@ -137,6 +137,34 @@ class TestFromSapSchema17_1RebaselineFields:
         assert result.assessment_type == "SAP"
 
 
+class TestFromSapSchema17_1DisplayElements:
+    """Display EnergyElements the WIP mapper dropped, leaving the FE
+    property-details panel "Unknown" for full-SAP certs (ADR-0037). Brings
+    full-SAP to parity with from_rdsap_schema_17_1's display coverage."""
+
+    @pytest.fixture
+    def result(self) -> EpcPropertyData:
+        schema = from_dict(SapSchema17_1, load("sap_17_1.json"))
+        return EpcPropertyDataMapper.from_sap_schema_17_1(schema)
+
+    def test_maps_main_heating_display_list(self, result: EpcPropertyData) -> None:
+        assert [e.description for e in result.main_heating] == [
+            "Boiler and radiators, mains gas"
+        ]
+
+    def test_maps_window_display_element(self, result: EpcPropertyData) -> None:
+        assert result.window is not None
+        assert result.window.description == "High performance glazing"
+
+    def test_maps_lighting_display_element(self, result: EpcPropertyData) -> None:
+        assert result.lighting is not None
+        assert result.lighting.description == "Low energy lighting in all fixed outlets"
+
+    def test_maps_hot_water_display_element(self, result: EpcPropertyData) -> None:
+        assert result.hot_water is not None
+        assert result.hot_water.description == "From main system"
+
+
 class TestFullSapHasHotWaterCylinderFallback:
     """Some full-SAP certs (e.g. SAP-Schema-17.0 cert 8265-7433-3220-9736-7902)
     omit the top-level `has_hot_water_cylinder` and lodge it only under