"""
Bollinger Bands 单元测试

Author: 张飞 翼德
Date: 2026-05-31
"""

import math
from bollinger import calc_bollinger


def test_basic():
    """基本功能测试"""
    prices = [float(10 + i) for i in range(25)]
    upper, middle, lower = calc_bollinger(prices, period=5)
    assert len(upper) == 21  # 25 - 5 + 1
    assert len(middle) == 21
    assert len(lower) == 21


def test_sma_correctness():
    """验证 middle 等于 SMA"""
    prices = [10.0, 11.0, 12.0, 13.0, 14.0]
    upper, middle, lower = calc_bollinger(prices, period=3)
    # SMA of [10,11,12] = 11.0
    assert math.isclose(middle[0], 11.0)
    # SMA of [11,12,13] = 12.0
    assert math.isclose(middle[1], 12.0)
    # SMA of [12,13,14] = 13.0
    assert math.isclose(middle[2], 13.0)


def test_upper_lower_symmetry():
    """验证上下轨关于中轨对称"""
    prices = [float(44 + i * 0.5 + (i % 3) * 0.2) for i in range(30)]
    upper, middle, lower = calc_bollinger(prices, period=10)
    for u, m, l in zip(upper, middle, lower):
        assert math.isclose(u - m, m - l, rel_tol=1e-9)


def test_upper_gt_middle_gt_lower():
    """上轨 > 中轨 > 下轨"""
    prices = [10.0, 11.0, 12.0, 13.0, 14.0, 15.0, 16.0, 17.0, 18.0, 19.0]
    upper, middle, lower = calc_bollinger(prices, period=5)
    for u, m, l in zip(upper, middle, lower):
        assert u > m > l


def test_num_std_zero():
    """num_std=0 → 三条线重合"""
    prices = [10.0, 11.0, 12.0, 13.0, 14.0]
    upper, middle, lower = calc_bollinger(prices, period=3, num_std=0.0)
    for u, m, l in zip(upper, middle, lower):
        assert math.isclose(u, m)
        assert math.isclose(m, l)


def test_insufficient_data():
    """数据不足 → 空列表"""
    prices = [10.0, 11.0, 12.0]
    upper, middle, lower = calc_bollinger(prices, period=5)
    assert upper == [] and middle == [] and lower == []


def test_period_invalid():
    """period <= 0"""
    prices = [10.0, 11.0, 12.0]
    upper, middle, lower = calc_bollinger(prices, period=0)
    assert upper == [] and middle == [] and lower == []
    upper, middle, lower = calc_bollinger(prices, period=-1)
    assert upper == [] and middle == [] and lower == []


def test_empty_input():
    """空输入"""
    upper, middle, lower = calc_bollinger([], period=5)
    assert upper == [] and middle == [] and lower == []


if __name__ == "__main__":
    test_basic()
    test_sma_correctness()
    test_upper_lower_symmetry()
    test_upper_gt_middle_gt_lower()
    test_num_std_zero()
    test_insufficient_data()
    test_period_invalid()
    test_empty_input()
    print("所有测试通过 ✅")