import numpy as np
import pytest

import scgenerator as sc


def test_scaling():
    period = 2
    nt = 512
    t = sc.tspace(period, nt)
    w = sc.wspace(t)
    dt = t[1] - t[0]
    assert w[1] - w[0] == pytest.approx(2 * np.pi / (period + dt))
    assert dt == pytest.approx(period / (nt - 1))


def test_wl_dispersion():
    t = sc.tspace(t_num=1 << 15, dt=3.8e-15)
    w = sc.wspace(t)
    wl = sc.units.m.inv(w + sc.units.nm(1546))
    wl_disp, ind_disp = sc.fiber.lambda_for_envelope_dispersion(wl, (950e-9, 4000e-9))
    assert all(np.diff(wl_disp) > 0)