UTests pass with Pathfinder2D

Gameboard.ShogiUI.UnitTests/PathFinding/PathFinder2DShould.cs

@@ -0,0 +1,46 @@
+using FluentAssertions;
+using Gameboard.ShogiUI.BoardState;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using PathFinding;
+using System.Collections.Generic;
+using System.Numerics;
+
+namespace Gameboard.ShogiUI.UnitTests.PathFinding
+{
+  [TestClass]
+  public class PathFinder2DShould
+  {
+    class TestElement : IPlanarElement
+    {
+      public ICollection<Path> GetPaths() => throw new System.NotImplementedException();
+      public bool IsUpsideDown => false;
+    }
+
+    [TestMethod]
+    public void Maths()
+    {
+      var finder = new PathFinder2D<TestElement>(new Array2D<TestElement>(5, 5));
+
+      var result = finder.IsPathable(
+        new Vector2(2, 2),
+        new Vector2(7, 7),
+        new Vector2(3, 3)
+        );
+      result.Should().BeTrue();
+
+      result = finder.IsPathable(
+        new Vector2(2, 2),
+        new Vector2(7, 7),
+        new Vector2(2, 2)
+        );
+      result.Should().BeFalse();
+
+      result = finder.IsPathable(
+        new Vector2(2, 2),
+        new Vector2(7, 7),
+        new Vector2(-1, 1)
+        );
+      result.Should().BeFalse();
+    }
+  }
+}