mrgameeng/tests/MrGameEng.Pathfinding.Tests/GridResizeTests.cs

using Microsoft.Xna.Framework;
using Xunit;

namespace MrGameEng.Pathfinding.Tests;

/// <summary>
/// Размеры грида фиксируются в конструкторе; «уехавший» грид должен давать
/// громкую ошибку, а не молчаливое чтение мимо границ.
/// </summary>
public class GridResizeTests
{
    private sealed class ResizableGrid : IPathGrid
    {
        public int Width { get; set; } = 4;

        public int Height { get; set; } = 4;

        public bool IsPassable(int x, int y) => true;

        public float Cost(int x, int y) => 1f;
    }

    [Fact]
    public void FindPath_AfterGridResize_Throws()
    {
        var grid = new ResizableGrid();
        var pathfinder = new GridPathfinder(grid);
        grid.Width = 8;

        Assert.Throws<InvalidOperationException>(() =>
            pathfinder.FindPath(new Point(0, 0), new Point(1, 1), [])
        );
    }

    [Fact]
    public void FlowFieldBuild_AfterGridResize_Throws()
    {
        var grid = new ResizableGrid();
        var builder = new FlowFieldBuilder(grid);
        grid.Height = 8;

        Assert.Throws<InvalidOperationException>(() =>
            builder.Build([new Point(0, 0)], new FlowField())
        );
    }
}