GodotComponentTest/tests/HexGridTests.cs

using System.Collections.Generic;
using System.Diagnostics;
using Godot;
using GoDotTest;
using Xunit;

public class HexGridTests : TestClass {
    public HexGridTests(Node testScene) : base(testScene) { }

    [Test]
    public void TestGetAt() {
        HexGrid grid = new();
        float w = grid.HexSize.x;
        float h = grid.HexSize.y;

        Debug.Assert(grid.GetHexAt(new Vector2(0, 0)).AxialCoords == new Vector2(0, 0));
        Debug.Assert(grid.GetHexAt(new Vector2(w / 2 - 0.01f, 0)).AxialCoords == new Vector2(0, 0));
        Debug.Assert(grid.GetHexAt(new Vector2(w / 2 - 0.01f, -h / 2)).AxialCoords == new Vector2(1, 0));
        Debug.Assert(grid.GetHexAt(new Vector2(w / 2 - 0.01f, h / 2)).AxialCoords == new Vector2(1, -1));
    }

    [Test]
    public void TestGetCellsForLineSimple() {
        HexGrid grid = new();

        List<HexCell> lineCells =
            grid.GetCellsForLine(new Vector2(0, 0), grid.GetHexCenterFromOffset(new Vector2(0, 2)));

        Assert.Equal(3, lineCells.Count);
        Assert.Equal(HexCell.FromOffsetCoords(new Vector2(0, 0)), lineCells[0]);
        Assert.Equal(HexCell.FromOffsetCoords(new Vector2(0, 1)), lineCells[1]);
        Assert.Equal(HexCell.FromOffsetCoords(new Vector2(0, 2)), lineCells[2]);

        lineCells =
            grid.GetCellsForLine(grid.GetHexCenterFromOffset(new Vector2(0, 2)), new Vector2(0, 0));

        Assert.Equal(3, lineCells.Count);
        Assert.Equal(HexCell.FromOffsetCoords(new Vector2(0, 2)), lineCells[0]);
        Assert.Equal(HexCell.FromOffsetCoords(new Vector2(0, 1)), lineCells[1]);
        Assert.Equal(HexCell.FromOffsetCoords(new Vector2(0, 0)), lineCells[2]);
    }

    [Test]
    public void TestGetCellsDiagonal() {
        HexGrid grid = new();

        List<HexCell> lineCells =
            grid.GetCellsForLine(new Vector2(0, 0), grid.GetHexCenterFromOffset(new Vector2(2, 1)));

        Assert.Equal(3, lineCells.Count);
        Assert.Equal(HexCell.FromOffsetCoords(new Vector2(0, 0)), lineCells[0]);
        Assert.Equal(HexCell.FromOffsetCoords(new Vector2(1, 0)), lineCells[1]);
        Assert.Equal(HexCell.FromOffsetCoords(new Vector2(2, 1)), lineCells[2]);

        lineCells =
            grid.GetCellsForLine(grid.GetHexCenterFromOffset(new Vector2(2, 1)), new Vector2(0, 0));

        Assert.Equal(3, lineCells.Count);
        Assert.Equal(HexCell.FromOffsetCoords(new Vector2(2, 1)), lineCells[0]);
        Assert.Equal(HexCell.FromOffsetCoords(new Vector2(1, 0)), lineCells[1]);
        Assert.Equal(HexCell.FromOffsetCoords(new Vector2(0, 0)), lineCells[2]);
    }

    [Test]
    public void TestGetCellsForLineAlongEdge() {
        HexGrid grid = new();

        List<HexCell> lineCells =
            grid.GetCellsForLine(new Vector2(0, -0.0001f), grid.GetHexCenterFromOffset(new Vector2(2, 0)));

        Assert.Equal(3, lineCells.Count);
        Assert.Equal(HexCell.FromOffsetCoords(new Vector2(0, 0)), lineCells[0]);
        Assert.Equal(HexCell.FromOffsetCoords(new Vector2(1, 0)), lineCells[1]);
        Assert.Equal(HexCell.FromOffsetCoords(new Vector2(2, 0)), lineCells[2]);

        lineCells =
            grid.GetCellsForLine(new Vector2(0, 0.0001f), grid.GetHexCenterFromOffset(new Vector2(2, 0)));

        Assert.Equal(3, lineCells.Count);
        Assert.Equal(HexCell.FromOffsetCoords(new Vector2(0, 0)), lineCells[0]);
        Assert.Equal(HexCell.FromOffsetCoords(new Vector2(1, -1)), lineCells[1]);
        Assert.Equal(HexCell.FromOffsetCoords(new Vector2(2, 0)), lineCells[2]);
    }

    [Test]
    public void GetTestsInfiniteLoop() {
        HexGrid grid = new();

        Vector2 fromPlane = new(-2.31678f, -5.024752f);
        Vector2 toPlane = new(-2.599937f, -6.134028f);

        List<HexCell> cellList = grid.GetCellsForLine(fromPlane, toPlane);
    }
}