"""Tests for Sheet 6: Commodity shock channel (Part VI)."""

import pytest
from fqbm.state import FQBMState
from fqbm.sheets.commodity import (
    inflation_composite,
    commodity_step,
    CommodityParams,
)


def test_inflation_composite():
    pi = inflation_composite(0.02, 0.1, 0.05, 0.1, 0.2)
    assert pi == pytest.approx(0.02 + 0.1 * 0.1 + 0.2 * 0.05)
    assert pi > 0.02


def test_commodity_step():
    state = FQBMState(O=1.0)
    params = CommodityParams(d_O=0.1)
    out = commodity_step(state, params)
    assert out.O == pytest.approx(1.1)
    params2 = CommodityParams(d_O=-0.05)
    out2 = commodity_step(out, params2)
    assert out2.O == pytest.approx(1.1 * 0.95)


def test_commodity_step_zero_o():
    state = FQBMState(O=0.0)
    params = CommodityParams(d_O=0.1)
    out = commodity_step(state, params)
    assert out.O == pytest.approx(1.1)