fuelboard-relay-api/tests/test_api_adapter.py

"""Unit tests for the FuelBoard Relay API adapter.

These exercise the normalisation layer against the DOCUMENTED Fuel Finder API
shapes (developer.fuel-finder.service.gov.uk) without any network access:
  - prices arrive as decimal strings in pence ("0120.0000" = 120.0p)
  - some stations report pounds (< 2.0 → multiply by 100)
  - lat/lng are strings inside a nested location object
  - two batched endpoints (station info + fuel prices) join on node_id
  - fuel types include B7_STANDARD / B7P / B10 (diesel variants), HVO, SDV
"""
import sys
from pathlib import Path

sys.path.insert(0, str(Path(__file__).resolve().parents[1] / "app"))

import main as relay


# ---------------------------------------------------------------------------
# _parse_price
# ---------------------------------------------------------------------------

class TestParsePrice:
    def test_pence_decimal_string(self):
        assert relay._parse_price("0120.0000") == 120.0

    def test_plain_number(self):
        assert relay._parse_price(137.9) == 137.9

    def test_pounds_denominated_multiplied(self):
        # Values below 2.0 are pounds: 1.299 → 129.9p
        assert relay._parse_price("1.299") == 129.9

    def test_null_price(self):
        assert relay._parse_price(None) is None

    def test_out_of_band_rejected(self):
        # 1589p / 1.3p-style garbage must not poison the cheapest reference
        assert relay._parse_price("1589.0000") is None
        assert relay._parse_price("0.013") is None

    def test_garbage_string(self):
        assert relay._parse_price("abc") is None
        assert relay._parse_price("") is None


# ---------------------------------------------------------------------------
# _normalise_api_payload (the node_id join)
# ---------------------------------------------------------------------------

class TestNormaliseApiPayload:
    def test_join_and_fuel_mapping(self):
        stations_info = [{
            "node_id": "abc123",
            "trading_name": "MORRISONS HALIFAX",
            "brand_name": "Morrisons",
            "location": {
                "address_line_1": "Haugh Shaw Road",
                "address_line_2": None,
                "postcode": "HX1 3TU",
                "latitude": "53.7265",
                "longitude": "-1.8580",
            },
            "is_motorway_service_station": False,
        }]
        fuel_prices = [{
            "node_id": "abc123",
            "trading_name": "MORRISONS HALIFAX",
            "fuel_prices": [
                {"price": "137.9000", "fuel_type": "E10", "price_last_updated": "2026-08-12T08:15:23"},
                {"price": "144.9000", "fuel_type": "E5", "price_last_updated": "2026-08-12T08:15:24"},
                {"price": "149.9000", "fuel_type": "B7_STANDARD", "price_last_updated": "2026-08-12T08:15:25"},
            ],
        }]

        stations = relay._normalise_api_payload(stations_info, fuel_prices)
        assert len(stations) == 1
        s = stations[0]
        assert s["id"] == "abc123"
        assert s["name"] == "MORRISONS HALIFAX"
        assert s["brand"] == "Morrisons"
        assert s["lat"] == 53.7265
        assert s["lng"] == -1.8580
        assert s["prices"] == {"E10": 137.9, "E5": 144.9, "DIESEL": 149.9}
        assert s["price_updated"] == "2026-08-12T08:15:25"

    def test_unpriced_fuel_dropped(self):
        stations_info = [{
            "node_id": "x1",
            "trading_name": "TEST",
            "location": {"latitude": "51.0", "longitude": "-1.0"},
        }]
        fuel_prices = [{
            "node_id": "x1",
            "fuel_prices": [
                {"price": None, "fuel_type": "E10", "price_last_updated": None},
            ],
        }]
        stations = relay._normalise_api_payload(stations_info, fuel_prices)
        # Station registered but no usable price → excluded
        assert stations == []

    def test_unmapped_fuel_types_ignored(self):
        stations_info = [{
            "node_id": "x2",
            "trading_name": "TEST",
            "location": {"latitude": "52.0", "longitude": "0.0"},
        }]
        fuel_prices = [{
            "node_id": "x2",
            "fuel_prices": [
                {"price": "180.0000", "fuel_type": "HVO", "price_last_updated": None},
                {"price": "190.0000", "fuel_type": "SDV", "price_last_updated": None},
            ],
        }]
        stations = relay._normalise_api_payload(stations_info, fuel_prices)
        assert stations == []  # nothing the app tracks

    def test_missing_station_info_skipped(self):
        stations_info = []  # info not yet in the join table
        fuel_prices = [{
            "node_id": "ghost",
            "fuel_prices": [{"price": "137.9000", "fuel_type": "E10"}],
        }]
        stations = relay._normalise_api_payload(stations_info, fuel_prices)
        assert stations == []

    def test_bad_lat_lng_strings(self):
        stations_info = [{
            "node_id": "y1",
            "trading_name": "BROKEN",
            "location": {"latitude": "not-a-number", "longitude": "-1.0"},
        }]
        fuel_prices = [{
            "node_id": "y1",
            "fuel_prices": [{"price": "137.9000", "fuel_type": "E10"}],
        }]
        stations = relay._normalise_api_payload(stations_info, fuel_prices)
        assert stations == []


# ---------------------------------------------------------------------------
# CSV fallback still parses (sibling relay behaviour preserved)
# ---------------------------------------------------------------------------

class TestCsvFallback:
    def test_parse_csv_to_stations(self):
        text = (
            "forecourts.node_id,forecourts.trading_name,forecourts.brand_name,"
            "forecourts.location.address_line_1,forecourts.location.postcode,"
            "forecourts.location.latitude,forecourts.location.longitude,"
            "forecourts.fuel_price.E10,forecourts.fuel_price.E5,forecourts.fuel_price.B7S\n"
            "c1,Morrisons Halifax,Morrisons,Haugh Shaw Road,HX1 3TU,"
            "53.7265,-1.8580,137.9,144.9,144.9\n"
            "c2,Tesco Express,Asda,,YO10 4AB,53.95,-1.08,,,\n"
        )
        stations = relay._parse_csv_to_stations(text)
        assert len(stations) == 1  # c2 sells nothing we track
        assert stations[0]["id"] == "c1"
        assert stations[0]["prices"] == {"E10": 137.9, "E5": 144.9, "DIESEL": 144.9}