TicTacToe { public void move(String place) { int row = place.charAt(0) - 'A'; int col = place.charAt(1) - '1'; if (b[row][col] != '_') { throw new IllegalArgumentException("Taken"); } b[row][col]=player ==0?'X':'0'; player = 1-player; } TicTacToe(); String getBoard(); void move(String place); Integer getWinner();  }
@Test(expected = IllegalArgumentException.class) public void A1A1throws() { tic.move("A1"); tic.move("A1"); }