Sheet sheet1 = (Sheet) book.getSheets().get(0);
assertEquals("#ff0000", ((SheetImpl)sheet1).getCell(1, 1).getFormat().getFillColor()); //B2
assertEquals("#008000", ((SheetImpl)sheet1).getCell(5, 1).getFormat().getFillColor()); //B6
//insert two columns
sheet1.insertColumns(2, 3);
assertEquals("#ff0000", ((SheetImpl)sheet1).getCell(1, 2).getFormat().getFillColor()); //C2
assertEquals("#008000", ((SheetImpl)sheet1).getCell(5, 2).getFormat().getFillColor()); //C6
assertEquals("#ff0000", ((SheetImpl)sheet1).getCell(1, 3).getFormat().getFillColor()); //D2
assertEquals("#008000", ((SheetImpl)sheet1).getCell(5, 3).getFormat().getFillColor()); //D6