s2rst 0.4.0

// SPDX-License-Identifier: Apache-2.0
// SPDX-FileCopyrightText: 2026 Torgeir Børresen <tb@starkad.no>

//! Original regression tests for [`super::S2DensityTree`]: an out-of-range
//! `max_level` is clamped to [`MAX_CELL_LEVEL`] instead of panicking in
//! `Level::from`. Written for this crate, not ported from upstream S2.

use super::*;
use crate::s2::LatLng;
use crate::s2::point_vector::PointVector;

fn point_index() -> ShapeIndex {
    let mut index = ShapeIndex::new();
    index.add(Box::new(PointVector::new(vec![
        LatLng::from_degrees(0.0, 0.0).to_point(),
        LatLng::from_degrees(1.0, 1.0).to_point(),
        LatLng::from_degrees(2.0, 2.0).to_point(),
    ])));
    index.build();
    index
}

#[test]
fn vertex_density_clamps_out_of_range_max_level() {
    let index = point_index();
    // Values above MAX_CELL_LEVEL must clamp instead of panicking.
    for max_level in [31u8, 50, 200, 255] {
        let mut tree = S2DensityTree::new();
        assert!(
            tree.init_to_vertex_density(&index, 1_000_000, max_level)
                .is_ok(),
            "max_level={max_level} should clamp, not panic"
        );
    }
}

#[test]
fn out_of_range_matches_max_cell_level() {
    let index = point_index();

    let mut clamped = S2DensityTree::new();
    clamped
        .init_to_vertex_density(&index, 1_000_000, 255)
        .unwrap();

    let mut at_max = S2DensityTree::new();
    at_max
        .init_to_vertex_density(&index, 1_000_000, MAX_CELL_LEVEL)
        .unwrap();

    assert_eq!(clamped.decode().unwrap(), at_max.decode().unwrap());
}

#[test]
fn breadth_first_builder_clamps_max_level() {
    // Constructing the builder with an out-of-range level must not panic.
    let mut b = BreadthFirstTreeBuilder::new(10_000, 200);
    let mut tree = S2DensityTree::new();
    assert!(b.build(|_cid| Ok(1), &mut tree).is_ok());
}

#[test]
fn sum_density_clamps_max_level() {
    let index = point_index();
    let mut t1 = S2DensityTree::new();
    t1.init_to_vertex_density(&index, 1_000_000, 10).unwrap();

    let mut sum = S2DensityTree::new();
    assert!(sum.init_to_sum_density(&[&t1], 255).is_ok());
}