from domain.postcodes.sanitise import sanitise_postcode


def test_sanitise_uppercases() -> None:
    assert sanitise_postcode("sw1a1aa") == "SW1A1AA"


def test_sanitise_strips_internal_spaces() -> None:
    assert sanitise_postcode("sw1a 1aa") == "SW1A1AA"


def test_sanitise_strips_leading_and_trailing_whitespace() -> None:
    assert sanitise_postcode("  sw1a 1aa  ") == "SW1A1AA"


def test_sanitise_strips_tabs_and_newlines() -> None:
    # CSV ingestion occasionally introduces stray whitespace characters; the
    # canonical form must absorb them just like literal spaces.
    assert sanitise_postcode("sw1a\t1aa\n") == "SW1A1AA"


def test_sanitise_already_canonical_is_idempotent() -> None:
    assert sanitise_postcode("SW1A1AA") == "SW1A1AA"
    assert sanitise_postcode(sanitise_postcode("sw1a 1aa")) == "SW1A1AA"


def test_sanitise_empty_string() -> None:
    assert sanitise_postcode("") == ""