public void TestMovementRule()
        {
            ChessBoard cb = new ChessBoard ();
            Pawn testPiece = new Pawn (cb [3, 2], "B");
            cb [3, 2].PlacePiece(testPiece);

            Assert.IsFalse (testPiece.CheckMovementRule (cb [3, 2], cb));
        }
        public void TestMovement()
        {
            ChessBoard cb = new ChessBoard ();
            Pawn testPiece = new Pawn (cb [3, 1], "B");
            cb [3, 1].PlacePiece(testPiece);

            Assert.AreEqual (testPiece.MovePiece (cb [4, 2], cb), "Invalid move");
            Assert.IsNull (testPiece.MovePiece (cb [3, 2],cb));
            Assert.AreSame (testPiece.Grid, cb [3, 2]);
            Assert.IsNull (testPiece.MovePiece (cb [3, 3], cb));

            Pawn testPiece2 = new Pawn (cb [4, 4], "W");
            cb [4, 4].PlacePiece(testPiece2);
            Assert.IsNull (testPiece.MovePiece (cb [4, 4], cb));
        }