from pathlib import Path
import sys

import pytest


SCRIPTS = Path(__file__).resolve().parents[1] / "scripts"
sys.path.insert(0, str(SCRIPTS))

from heat_compute_metrics import estimate_captured_heat, heat_reuse_factor  # noqa: E402


def test_estimates_captured_heat_from_it_energy_and_capture_factor():
    captured = estimate_captured_heat(
        it_energy_kwh=1000,
        capture_factor=0.9,
    )

    assert captured == pytest.approx(900)


def test_heat_reuse_factor_counts_only_heat_delivered_to_a_real_host():
    reuse = heat_reuse_factor(
        heat_delivered_to_host_kwh=450,
        heat_rejected_kwh=900,
    )

    assert reuse == pytest.approx(0.5)