import math, pytest
from matrixmania import rot_3D

def test_rot_3D_x_axis():
    angle = math.pi / 2
    R = rot_3D(angle, 'x')
    expected = [
        [1, 0, 0],
        [0, 0, -1],
        [0, 1, 0]
    ]
    for r, e in zip(R, expected):
        for rv, ev in zip(r, e):
            assert math.isclose(rv, ev, abs_tol=1e-9)

def test_rot_3D_invalid_axis():
    with pytest.raises(ValueError):
        rot_3D(math.pi/4, 'a')