Worksheet sheet1 = _workbook.getWorksheet("Sheet1");
Row row1 = sheet1.getRow(0);
Cell A1 = BookHelper.getOrCreateCell(sheet1, 0, 0);
CellStyle newCellStyle = _workbook.createCellStyle();
newCellStyle.cloneStyleFrom(A1.getCellStyle());
final Color bsColor = BookHelper.HTMLToColor(_workbook, "#00FF00");
BookHelper.setFillForegroundColor(newCellStyle, bsColor);
BookHelper.setCellStyle(sheet1, 0, 0, 0, 0, newCellStyle);
assertEquals("FF00FF00", ((XSSFColor)row1.getCell(0).getCellStyle().getFillForegroundColorColor()).getARGBHex()); //A1: Green
}