perfect-postcode/finder/test_transform.py

from transform import (
    build_register_address,
    clean_listing_address,
    extract_full_postcode,
    extract_outcode,
    resolve_listing_postcode,
    transform_property,
)


class StubPostcodeIndex:
    def __init__(self, postcode: str = "SW1A 9ZZ") -> None:
        self._postcode = postcode

    def nearest(self, lat: float, lng: float) -> str:
        return self._postcode


def test_extract_full_postcode_normalizes_spacing() -> None:
    assert extract_full_postcode("10 Downing Street SW1A2AA") == "SW1A 2AA"
    assert extract_full_postcode("10 Downing Street, SW1A 2AA") == "SW1A 2AA"
    assert extract_full_postcode("Downing Street, Westminster") is None


def test_clean_listing_address_removes_postcode_and_outcode_suffixes() -> None:
    assert clean_listing_address("10 Downing Street, SW1A 2AA") == "10 Downing Street"
    assert clean_listing_address("Hawthorne Road, Bromley, Kent, BR1") == (
        "Hawthorne Road, Bromley, Kent"
    )
    assert clean_listing_address("Kings Avenue, Bromley") == "Kings Avenue, Bromley"


def test_build_register_address_prepends_house_number_or_name() -> None:
    # House number/name prepended, with the trailing outcode/postcode stripped.
    assert (
        build_register_address("South Street, Bromley BR1", "12")
        == "12, South Street, Bromley"
    )
    assert (
        build_register_address("Riverside, Martham NR29", "Martham Mill")
        == "Martham Mill, Riverside, Martham"
    )
    # No number/name -> identical to the plain cleaned address.
    assert build_register_address("Kings Avenue, Bromley", None) == "Kings Avenue, Bromley"
    # Already starts with the number/name -> no duplication.
    assert (
        build_register_address("12 South Street, Bromley", "12")
        == "12 South Street, Bromley"
    )
    # Empty/whitespace number/name is ignored.
    assert build_register_address("Kings Avenue, Bromley", "  ") == "Kings Avenue, Bromley"


def test_extract_outcode() -> None:
    assert extract_outcode("SW1A 2AA") == "SW1A"
    assert extract_outcode("n4 2ha") == "N4"
    assert extract_outcode("SW1A2AA") == "SW1A"
    assert extract_outcode(None) is None
    assert extract_outcode("") is None


def test_resolve_listing_postcode() -> None:
    # Outcode matches -> trust the more precise extracted postcode.
    assert resolve_listing_postcode("SW1A 2AA", "SW1A 9ZZ") == ("SW1A 2AA", "address")
    # Outcode mismatch -> fall back to the spatially-correct inferred postcode.
    assert resolve_listing_postcode("E14 9SS", "SW1A 9ZZ") == ("SW1A 9ZZ", "coordinates")
    # Well-formed but fabricated postcode in a different outcode is rejected.
    assert resolve_listing_postcode("ZZ9 9ZZ", "SW1A 9ZZ") == ("SW1A 9ZZ", "coordinates")
    # No extracted postcode -> inferred is authoritative.
    assert resolve_listing_postcode(None, "SW1A 9ZZ") == ("SW1A 9ZZ", "coordinates")


def test_rightmove_transform_prefers_postcode_from_display_address() -> None:
    prop = {
        "id": "123",
        "location": {"latitude": 51.5, "longitude": -0.1},
        "price": {"amount": 750000, "displayPrices": []},
        "propertySubType": "Terraced",
        "bedrooms": 3,
        "bathrooms": 1,
        "keyFeatures": [],
        "propertyUrl": "/properties/123",
        "displayAddress": "Flat 2, 10 Downing Street, SW1A 2AA",
    }

    result = transform_property(prop, "SW1A", StubPostcodeIndex())

    assert result is not None
    assert result["Postcode"] == "SW1A 2AA"
    assert result["Postcode source"] == "address"
    assert result["Extracted postcode"] == "SW1A 2AA"
    assert result["Inferred postcode"] == "SW1A 9ZZ"
    assert result["Listing raw address"] == "Flat 2, 10 Downing Street, SW1A 2AA"
    assert result["Address per Property Register"] == "Flat 2, 10 Downing Street"


def test_rightmove_transform_rejects_postcode_from_wrong_outcode() -> None:
    prop = {
        "id": "124",
        "location": {"latitude": 51.5, "longitude": -0.1},
        "price": {"amount": 750000, "displayPrices": []},
        "propertySubType": "Terraced",
        "bedrooms": 3,
        "bathrooms": 1,
        "keyFeatures": [],
        "propertyUrl": "/properties/124",
        # Address postcode is in a different outcode than the coordinate-nearest one.
        "displayAddress": "10 Downing Street, E14 9SS",
    }

    result = transform_property(prop, "SW1A", StubPostcodeIndex())

    assert result is not None
    # The spatially-correct inferred postcode wins over the mismatching extracted one.
    assert result["Postcode"] == "SW1A 9ZZ"
    assert result["Postcode source"] == "coordinates"
    assert result["Extracted postcode"] == "E14 9SS"


def _rightmove_prop() -> dict:
    return {
        "id": "200",
        "location": {"latitude": 51.5, "longitude": -0.1},
        "price": {"amount": 750000, "displayPrices": []},
        "propertySubType": "Terraced",
        "bedrooms": 3,
        "bathrooms": 1,
        "keyFeatures": [],
        "propertyUrl": "/properties/200",
        # Search API only ever exposes the outcode in the display address.
        "displayAddress": "Caldwell Street, Stockwell, SW9",
    }


def test_rightmove_transform_prefers_detail_postcode() -> None:
    # The detail page's true full postcode (same outcode as the location) is
    # preferred over the coordinate-nearest guess.
    result = transform_property(
        _rightmove_prop(),
        "SW9",
        StubPostcodeIndex("SW9 7AA"),
        detail_postcode="SW9 0HD",
    )

    assert result is not None
    assert result["Postcode"] == "SW9 0HD"
    assert result["Postcode source"] == "detail_address"
    # The coordinate inference is still surfaced separately.
    assert result["Inferred postcode"] == "SW9 7AA"


def test_rightmove_transform_rejects_detail_postcode_from_wrong_outcode() -> None:
    # A detail postcode whose outcode disagrees with the location must not
    # relocate the listing; the coordinate postcode wins instead.
    result = transform_property(
        _rightmove_prop(),
        "SW9",
        StubPostcodeIndex("SW9 7AA"),
        detail_postcode="E14 9SS",
    )

    assert result is not None
    assert result["Postcode"] == "SW9 7AA"
    assert result["Postcode source"] == "coordinates"


def test_rightmove_transform_without_detail_keeps_coordinate_logic() -> None:
    # No detail postcode -> behaviour is unchanged (coordinate-nearest).
    result = transform_property(
        _rightmove_prop(), "SW9", StubPostcodeIndex("SW9 7AA")
    )

    assert result is not None
    assert result["Postcode"] == "SW9 7AA"
    assert result["Postcode source"] == "coordinates"