public void OnButtonClick(object sender, EventArgs a)
    {
        ((Button)sender).Text    = humanSide;
        ((Button)sender).Enabled = false;

        for (int i = 0; i < 3; i++)
        {
            for (int j = 0; j < 3; j++)
            {
                if (sender == squares[i, j])
                {
                    t.PlayMove(TicTacToe.HUMAN, i, j);
                }
            }
        }

        if (ResetIfDone(t.BoardIsFull( ), "DRAW", true))
        {
            return;
        }

        DoCompMove(true);
        ResetIfDone(t.IsAWin(TicTacToe.COMPUTER), "I WIN!!", true);
        ResetIfDone(t.BoardIsFull( ), "DRAW", false);

        return;
    }
        public void BoardIsFullReturnsTrueWhenBoardIsFull()
        {
            var instance = new TicTacToe();

            FillBoard(instance);

            Assert.IsTrue(instance.BoardIsFull());
        }