Coerce banded flat_location string to its floor integer 🟥

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

datatypes/epc/domain/tests/test_from_rdsap_schema.py

@@ -458,6 +458,23 @@ class TestFromRdSapSchema21_0_1:
 
         assert result.led_fixed_lighting_bulbs_count == 0
 
+    def test_banded_flat_location_string_coerced_to_band_floor_int(self) -> None:
+        # The gov API lodges flat_location (the flat's floor number) as a plain
+        # int on most certs, but on high floors as a banded string "20+" (floor
+        # 20 or above) — e.g. cert 2481-2122-4211-1172-4722 (UPRN 6027561).
+        # The epc_flat_details.flat_location column is a NOT-NULL integer, so the
+        # raw string crashed the modelling_e2e insert (psycopg2
+        # InvalidTextRepresentation, portfolio 796 run). Coerce the band to its
+        # floor (20); Elmhurst caps the floor number at 30.
+        data = load("21_0_1.json")
+        data["sap_flat_details"]["flat_location"] = "20+"
+        schema = from_dict(RdSapSchema21_0_1, data)
+
+        result = EpcPropertyDataMapper.from_rdsap_schema_21_0_1(schema)
+
+        assert result.sap_flat_details is not None
+        assert result.sap_flat_details.flat_location == 20
+
     def test_uprn(self, result: EpcPropertyData) -> None:
         assert result.uprn == 12457