# -*- coding: utf-8 -*-
from math import pi
import pytest

import pygmsh

from helpers import compute_volume


@pytest.mark.skipif(pygmsh.get_gmsh_major_version() < 3, reason="requires Gmsh >= 3")
def test():
    geom = pygmsh.opencascade.Geometry()

    geom.add_ball(
        [0.0, 0.0, 0.0], 1.0, x0=-0.9, x1=+0.9, alpha=0.5 * pi, char_length=0.1
    )

    ref = 0.976088698545
    points, cells, _, _, _ = pygmsh.generate_mesh(geom)
    assert abs(compute_volume(points, cells) - ref) < 1.0e-2 * ref
    return points, cells


if __name__ == "__main__":
    import meshio

    meshio.write_points_cells("opencascade_ball.vtu", *test())
