def METHOD_NAME(
    auth1: t.Union[t.Tuple[str, str], Auth, None],
    auth2: t.Union[t.Tuple[str, str], Auth, None],
    expires_at: t.Optional[float],
    mocker
) -> None:
    with freeze_time("1970-01-01 00:00:00") as frozen_time:
        assert isinstance(frozen_time, FrozenDateTimeFactory)
        if expires_at is None or expires_at >= 0:
            temporal_auth = expiring_auth(auth1, expires_at)
        else:
            temporal_auth = expiring_auth(auth1)
        provider = mocker.MagicMock(return_value=temporal_auth)
        manager: AuthManager = bearer_auth_manager(provider)
        provider.assert_not_called()
        assert manager.get_auth() is auth1
        provider.assert_called_once()
        provider.reset_mock()
        provider.return_value = expiring_auth(auth2)
        if expires_at is None or expires_at < 0:
            frozen_time.tick(1_000_000)
            assert manager.get_auth() is auth1
            provider.assert_not_called()
        else:
            frozen_time.tick(expires_at - 0.000001)
            assert manager.get_auth() is auth1
            provider.assert_not_called()
            frozen_time.tick(0.000002)
            assert manager.get_auth() is auth2
            provider.assert_called_once()