Withhold roof insulation from RIR surfaces the surveyor marked insulation-unknown 🟥

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

datatypes/epc/domain/tests/test_from_site_notes.py

@@ -252,6 +252,50 @@ class TestRoomInRoofMapping:
         # Assert
         assert result.sap_building_parts[0].sap_room_in_roof is None
 
+    def test_insulation_not_threaded_when_surveyor_answered_not_known(
+        self,
+    ) -> None:
+        """On the survey form that asks per surface "Are you able to provide
+        details of the insulation …?", a "No" means the surveyor could NOT
+        confirm insulation for that surface (fixture 499617935574: loft hatch
+        screwed shut) — the roof-space thickness must not be threaded into it,
+        leaving the Table 18 col(4) age-band "unknown" default. Common walls
+        are never asked on this form, so they stay unthreaded too. The
+        legacy form (no question lodged anywhere; the `_RIR` fixture above)
+        keeps threading — pinned by `test_room_in_roof_reaches_building_part`.
+        """
+        # Arrange — the verbatim 499617935574 answers: gables Yes, slopes and
+        # flat ceiling No, common walls never asked.
+        data = load("pashub_rdsap_site_notes_example1.json")
+        data["roof_space"]["main_building"]["rooms_in_roof"] = True
+        rir = json.loads(json.dumps(self._RIR))
+        for gable in rir["gables"]:
+            gable["insulation_known"] = True
+        for slope in rir["slopes"]:
+            slope["insulation_known"] = False
+        rir["flat_ceilings"][0]["insulation_known"] = False
+        data["roof_space"]["main_building"]["room_in_roof"] = rir
+        survey = from_dict(PasHubRdSapSiteNotes, data)
+
+        # Act
+        mapped = EpcPropertyDataMapper.from_site_notes(survey).sap_building_parts[
+            0
+        ].sap_room_in_roof
+
+        # Assert
+        assert mapped is not None
+        surfaces = mapped.detailed_surfaces
+        assert surfaces is not None
+        assert [(s.kind, s.insulation_thickness_mm) for s in surfaces] == [
+            ("gable_wall_external", None),
+            ("gable_wall", None),
+            ("slope", None),
+            ("slope", None),
+            ("stud_wall", None),
+            ("stud_wall", None),
+            ("flat_ceiling", None),
+        ]
+
 
 class TestSystemBuildWallIsNotBasement:
     """RdSAP wall-construction code 6 is overloaded: PasHub "System Build