it fricken works!

Gameboard.ShogiUI.UnitTests/BoardState/ShogiBoardShould.cs

@@ -1,6 +1,7 @@
 using FluentAssertions;
 using Gameboard.ShogiUI.BoardState;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
+using System;
 using System.Linq;
 using System.Numerics;
 
@@ -304,15 +305,22 @@ namespace Gameboard.ShogiUI.UnitTests.BoardState
         new Move { From = new Vector2(4, 4), To = new Vector2(4, 5) },
         // P2 King
         new Move { From = new Vector2(4, 8), To = new Vector2(4, 7) },
-        // P1 Pawn promotes
+        // P1 Pawn promotes, threatens P2 King
         new Move { From = new Vector2(4, 5), To = new Vector2(4, 6), IsPromotion = true },
         // P2 King retreat
         new Move { From = new Vector2(4, 7), To = new Vector2(4, 8) },
       };
       var shogi = new ShogiBoard(moves);
+      Console.WriteLine("Prereq");
+      shogi.PrintStateAsAscii();
 
       // Act - P1 Pawn wins by checkmate.
       var moveSuccess = shogi.Move(new Move { From = new Vector2(4, 6), To = new Vector2(4, 7) });
+      Console.WriteLine("Checkmate");
+      shogi.PrintStateAsAscii();
+
+      shogi.Move(new Move { From = new Vector2(4, 8), To = new Vector2(4, 7) });
+      shogi.PrintStateAsAscii();
 
       // Assert
       moveSuccess.Should().BeTrue();