import numpy as np

from irae_risk.monotonic import forward_map


def test_forward_map_is_invariant_under_parameter_sign_symmetries():
    theta = np.array([1.2, 0.7, -1.5, 2.3])
    expected = forward_map(theta)

    equivalent_theta = (
        theta * np.array([1, -1, 1, 1]),
        theta * np.array([1, 1, -1, -1]),
        theta * np.array([1, -1, -1, -1]),
    )

    for equivalent in equivalent_theta:
        np.testing.assert_allclose(forward_map(equivalent), expected)