test: add failing tests for get_col_to_description_mappings

Drive the contract for LandlordDescriptionOverridesOrchestrator.
get_col_to_description_mappings: given a list of UserAddress sharing
the same landlord_additional_info keys, return each key mapped to the
list of values found across all addresses.

Tests are red — the method still raises NotImplementedError.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

orchestration/landlord_description_overrides_orchestrator.py

@@ -0,0 +1,19 @@
+from repositories.user_address.user_address_repository import UserAddressRepository
+from domain.addresses.user_address import UserAddress
+
+
+class LandlordDescriptionOverridesOrchestrator:
+    def __init__(self, user_address_repo: UserAddressRepository) -> None:
+        self._user_address_repo = user_address_repo
+
+    def get_user_address(
+        self,
+        input_s3_uri: str,
+    ) -> list[UserAddress]:
+        return self._user_address_repo.load_batch(input_s3_uri)
+
+    def get_col_to_description_mappings(
+        self, list_of_user_address: list[UserAddress]
+    ) -> dict[str, list[str]]:
+
+        raise NotImplementedError()

tests/orchestration/test_landlord_description_overrides_orchestrator.py

@@ -0,0 +1,69 @@
+from __future__ import annotations
+
+from domain.addresses.user_address import UserAddress
+from domain.postcode import Postcode
+from orchestration.landlord_description_overrides_orchestrator import (
+    LandlordDescriptionOverridesOrchestrator,
+)
+from repositories.user_address.user_address_repository import UserAddressRepository
+
+
+class _StubUserAddressRepository(UserAddressRepository):
+    """``get_col_to_description_mappings`` never touches the repo."""
+
+    def load_batch(self, s3_uri: str) -> list[UserAddress]:
+        raise NotImplementedError()
+
+    def save_batch(self, addresses: list[UserAddress], path_prefix: str) -> str:
+        raise NotImplementedError()
+
+
+def _make_user_address(landlord_additional_info: dict[str, str]) -> UserAddress:
+    return UserAddress(
+        user_address="1 High St",
+        postcode=Postcode("AA1 1AA"),
+        landlord_additional_info=landlord_additional_info,
+    )
+
+
+def _orchestrator() -> LandlordDescriptionOverridesOrchestrator:
+    return LandlordDescriptionOverridesOrchestrator(
+        user_address_repo=_StubUserAddressRepository()
+    )
+
+
+def test_collects_every_value_per_shared_key() -> None:
+    # arrange: every address carries the same keys, all values distinct.
+    addresses = [
+        _make_user_address({"description": "cosy", "condition": "new"}),
+        _make_user_address({"description": "spacious", "condition": "worn"}),
+        _make_user_address({"description": "bright", "condition": "fair"}),
+    ]
+
+    # act
+    mappings = _orchestrator().get_col_to_description_mappings(addresses)
+
+    # assert
+    assert mappings == {
+        "description": ["cosy", "spacious", "bright"],
+        "condition": ["new", "worn", "fair"],
+    }
+
+
+def test_empty_address_list_yields_empty_mapping() -> None:
+    # arrange / act
+    mappings = _orchestrator().get_col_to_description_mappings([])
+
+    # assert
+    assert mappings == {}
+
+
+def test_single_address_yields_single_value_per_key() -> None:
+    # arrange
+    addresses = [_make_user_address({"description": "cosy"})]
+
+    # act
+    mappings = _orchestrator().get_col_to_description_mappings(addresses)
+
+    # assert
+    assert mappings == {"description": ["cosy"]}