From 4e291e4184d37104195dac68c209511cf7d13c0f Mon Sep 17 00:00:00 2001
From: Khalim Conn-Kowlessar <kconnkowlessar@gmail.com>
Date: Mon, 13 Jul 2026 15:03:55 +0000
Subject: [PATCH] =?UTF-8?q?Resolve=20landlord=20references=20to=20UPRNs,?=
 =?UTF-8?q?=20excluding=20unresolved=20rows=20=F0=9F=9F=A5?=
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Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 .../condition/property_reference_reader.py    | 19 +++++++++++
 .../condition/property_uprn_lookup.py         | 18 +++++++++++
 .../lookups/test_property_uprn_lookup.py      | 32 +++++++++++++++++++
 3 files changed, 69 insertions(+)
 create mode 100644 repositories/condition/property_reference_reader.py
 create mode 100644 repositories/condition/property_uprn_lookup.py
 create mode 100644 tests/condition/lookups/test_property_uprn_lookup.py

diff --git a/repositories/condition/property_reference_reader.py b/repositories/condition/property_reference_reader.py
new file mode 100644
index 000000000..1eba7524e
--- /dev/null
+++ b/repositories/condition/property_reference_reader.py
@@ -0,0 +1,19 @@
+from abc import ABC, abstractmethod
+from dataclasses import dataclass
+from typing import List, Optional
+
+
+@dataclass(frozen=True)
+class PropertyReference:
+    """A property's landlord reference and resolved UPRN, as held in the
+    ``property`` table. ``uprn`` is nullable — a property whose UPRN has not been
+    resolved yet cannot receive condition rows."""
+
+    landlord_property_id: Optional[str]
+    uprn: Optional[int]
+
+
+class PropertyReferenceReader(ABC):
+    @abstractmethod
+    def references_for_portfolio(self, portfolio_id: int) -> List[PropertyReference]:
+        ...
diff --git a/repositories/condition/property_uprn_lookup.py b/repositories/condition/property_uprn_lookup.py
new file mode 100644
index 000000000..b9c8e4e2a
--- /dev/null
+++ b/repositories/condition/property_uprn_lookup.py
@@ -0,0 +1,18 @@
+from typing import Dict
+
+from repositories.condition.property_reference_reader import PropertyReferenceReader
+from repositories.condition.uprn_lookup import UprnLookup
+
+
+class PropertyUprnLookup(UprnLookup):
+    """Resolves a landlord property reference to a UPRN from the ``property``
+    table, scoped to one portfolio (ADR-0064)."""
+
+    def __init__(
+        self, reader: PropertyReferenceReader, portfolio_id: int
+    ) -> None:
+        self._reader = reader
+        self._portfolio_id = portfolio_id
+
+    def get_property_ref_to_uprn_lookup(self) -> Dict[str, int]:
+        raise NotImplementedError
diff --git a/tests/condition/lookups/test_property_uprn_lookup.py b/tests/condition/lookups/test_property_uprn_lookup.py
new file mode 100644
index 000000000..f303b55f1
--- /dev/null
+++ b/tests/condition/lookups/test_property_uprn_lookup.py
@@ -0,0 +1,32 @@
+from typing import List
+
+from repositories.condition.property_reference_reader import (
+    PropertyReference,
+    PropertyReferenceReader,
+)
+from repositories.condition.property_uprn_lookup import PropertyUprnLookup
+
+
+class FakePropertyReferenceReader(PropertyReferenceReader):
+    def __init__(self, references: List[PropertyReference]) -> None:
+        self._references = references
+
+    def references_for_portfolio(self, portfolio_id: int) -> List[PropertyReference]:
+        return self._references
+
+
+def test_property_uprn_lookup_excludes_rows_with_no_uprn():
+    # Arrange
+    reader = FakePropertyReferenceReader(
+        [
+            PropertyReference(landlord_property_id="443", uprn=100093305101),
+            PropertyReference(landlord_property_id="999", uprn=None),
+        ]
+    )
+    lookup = PropertyUprnLookup(reader, portfolio_id=824)
+
+    # Act
+    mapping = lookup.get_property_ref_to_uprn_lookup()
+
+    # Assert
+    assert mapping == {"443": 100093305101}