"""Unit tests for services/district_service.py."""

import pytest

from services import district_service


class TestGetAllDistricts:
    def test_get_all_districts_returns_dict(self):
        result = district_service.get_all_districts()
        assert isinstance(result, dict)
        assert len(result) > 0


class TestGetDistrictNames:
    def test_get_district_names_returns_list(self):
        result = district_service.get_district_names()
        assert isinstance(result, list)
        assert len(result) > 0


class TestValidateDistricts:
    def test_validate_districts_all_valid(self):
        result = district_service.validate_districts(["London", "Westminster"])
        assert result == []

    def test_validate_districts_returns_invalid(self):
        result = district_service.validate_districts(["London", "Narnia"])
        assert "Narnia" in result

    def test_known_districts_present(self):
        names = district_service.get_district_names()
        for district in ["London", "Westminster", "Camden"]:
            assert district in names