Quadtree/QuadtreeTests/Tests.cs

using NSubstitute;
using SpatialCollections;
using System.Numerics;

namespace QuadtreeTests
{
    public class Tests
    {
        private class TestWorldObject(Vector2 position) : IWorldObject
        {
            public Vector2 Position { get; } = position;

            public float BoundingRadius { get; } = 1.0f;

            public BoundingBox2 BoundingBox { get; } = new BoundingBox2(position - Vector2.One, position + Vector2.One);
        }

        private List<Vector2> _positions;

        private List<IWorldObject> _objects;

        private Quadtree _quadtree;

        [SetUp]
        public void Setup()
        {
            _positions = [new Vector2(1.0f, 1.0f), new Vector2(3.0f, 3.0f), new Vector2(5.0f, 8.0f)];
            _objects = new();
            _quadtree = new(20, 4);

            for (int i = 0; i < _positions.Count; i++)
            {
                var obj = new TestWorldObject(_positions[i]);
                _objects.Add(obj);
            }
        }

        [Test]
        public void TestAdd()
        {
            AddObjectsAndAssertCount();
        }

        [Test]
        public void TestAddRemove()
        {
            AddObjectsAndAssertCount();

            for (int i = 0; i < _objects.Count; i++)
            {
                _quadtree.Remove(_objects[i]);
                Assert.That(_quadtree.Count, Is.EqualTo(_objects.Count - i - 1));
            }
        }

        [Test]
        public void TestQuery()
        {
            AddObjectsAndAssertCount();
            List<IWorldObject> result = new();
            _quadtree.Query(new BoundingBox2(new Vector2(3.5f, 3.5f), new Vector2(10.0f, 10.0f)), result);
            Assert.That(result.Count, Is.EqualTo(2));
        }

        private void AddObjectsAndAssertCount()
        {
            for (int i = 0; i < _objects.Count; i++)
            {
                _quadtree.Add(_objects[i]);
                Assert.That(_quadtree.Count, Is.EqualTo(i + 1));
            }
        }
    }
}