Sheet sheet = wb.createSheet();
Row row = sheet.createRow(0);
row.createCell(0).setCellValue(1.1);
row.createCell(1).setCellValue(2.2);
CellRangeAddress region = new CellRangeAddress(0, 0, 0, 2);
assertEquals("A1:C1", region.formatAsString());
sheet.addMergedRegion(region);
sheet.shiftRows(0, 1, 2);
region = sheet.getMergedRegion(0);