"""Tests for the Redis cursor."""

import fakeredis.aioredis

from services.kevin_signal_bridge.cursor import RedisCursor


async def _redis():
    return fakeredis.aioredis.FakeRedis()


async def test_cursor_defaults_to_zero():
    cursor = RedisCursor(await _redis())
    assert await cursor.last_seen_id() == 0


async def test_cursor_advance_persists_value():
    cursor = RedisCursor(await _redis())
    await cursor.advance(42)
    assert await cursor.last_seen_id() == 42


async def test_cursor_advance_never_goes_backwards():
    cursor = RedisCursor(await _redis())
    await cursor.advance(42)
    await cursor.advance(10)
    assert await cursor.last_seen_id() == 42