# -*- coding: utf-8 -*-
"""Unit tests: common target (Forward Return / ATR) and ATR no-lookahead."""
import numpy as np
import pytest

from src.forecasting.target import forward_return, data_atr


def test_forward_return_uses_atr_denominator():
    close = [1.0, 2.0, 3.0, 4.0, 5.0]
    atr = [1.0, 1.0, 1.0, 1.0, 1.0]
    assert forward_return(close, atr, 0, 2) == pytest.approx(3.0 - 1.0)


def test_forward_return_reachable():
    close = list(np.linspace(100.0, 101.5, 15))
    atr = data_atr(close, 5)
    y = forward_return(close, atr, 5, 4)
    assert np.isfinite(y)


def test_atr_no_lookahead():
    close = np.asarray(np.linspace(100, 110, 50), dtype=float)
    atr = data_atr(close, 10)
    # mutating future bars must not change ATR at earlier indices
    close2 = close.copy()
    close2[20:] += 5000.0
    atr2 = data_atr(close2, 10)
    assert np.allclose(atr[9:19], atr2[9:19])