"""Tests for `hash_tip_data` — the dismissal-expiry fingerprint.

See `app.entities.tip_dismissal.TipDismissal` and
`TipsService._drop_stale_dismissed`: a dismissal only stays silent while the
rule's `data` still hashes the same. These tests pin the two properties that
matter for that contract: stability (same data → same hash, regardless of
key order) and sensitivity (any value change → a different hash).
"""

from app.utils.tip_predicates import hash_tip_data


class TestHashTipData:
    def test_stable_regardless_of_key_order(self) -> None:
        a = hash_tip_data({"parent_name": "Alice", "expiring_days": 12})
        b = hash_tip_data({"expiring_days": 12, "parent_name": "Alice"})
        assert a == b

    def test_changes_when_a_value_changes(self) -> None:
        a = hash_tip_data({"parent_name": "Alice", "expiring_days": 12})
        b = hash_tip_data({"parent_name": "Alice", "expiring_days": 13})
        assert a != b

    def test_changes_when_a_key_is_added_or_removed(self) -> None:
        a = hash_tip_data({"parent_name": "Alice"})
        b = hash_tip_data({"parent_name": "Alice", "expiring_days": 12})
        assert a != b

    def test_empty_data_hashes_consistently(self) -> None:
        assert hash_tip_data({}) == hash_tip_data({})