Dispatch and map RdSAP-Schema-17.1 certs end-to-end 🟥

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

datatypes/epc/domain/tests/test_from_rdsap_schema.py

@@ -1705,3 +1705,42 @@ class TestRdSap18_0ReducedFieldSynthesis:
         # Assert
         assert result.sap_heating.number_baths == expected_baths
         assert result.sap_heating.mixer_shower_count == expected_mixers
+
+
+# ---------------------------------------------------------------------------
+# RdSAP 17.1 Reduced-Field Synthesis (ADR-0028 — inherit-and-validate). 17.1 is
+# the same pre-SAP10 reduced family as 18.0/20.0.0 and reuses the same inherited
+# 20.0.0 coefficients via the shared `_synthesise_reduced_field_windows` core;
+# its own band-4 rich certs validate the transfer. Each test name pins one
+# synthesis assumption (Validation-Cohort rule: no same-spec lodged figure).
+# ---------------------------------------------------------------------------
+
+_CORPUS_17_1 = os.path.join(
+    os.path.dirname(__file__),
+    "../../../../backend/epc_api/json_samples/RdSAP-Schema-17.1/corpus.jsonl",
+)
+
+
+def _load_17_1_corpus() -> list[Dict[str, Any]]:
+    if not os.path.exists(_CORPUS_17_1):
+        return []
+    with open(_CORPUS_17_1) as f:
+        return [json.loads(line) for line in f if line.strip()]
+
+
+class TestRdSap17_1ReducedFieldSynthesis:
+
+    def test_cert_dispatches_and_maps_without_missing_required_field(self) -> None:
+        # Arrange — the placeholder 17.1 schema over-constrains (only 4/1000
+        # parse) and `from_api_response` never dispatched RdSAP-Schema-17.1.
+        # Dispatch + required→optional must let a real cert through end-to-end.
+        corpus = _load_17_1_corpus()
+        if not corpus:
+            pytest.skip("no RdSAP-Schema-17.1 corpus harvested")
+        cert = corpus[0]
+
+        # Act
+        result = EpcPropertyDataMapper.from_api_response(cert)
+
+        # Assert
+        assert isinstance(result, EpcPropertyData)