@Test
public void addCellValueToTest(){

    // given
    XSSFWorkbook workbook = new XSSFWorkbook();
    XSSFSheet sheet = workbook.createSheet();
    Row r = sheet.createRow(0);
    // when source null
    Cell cSource = null;
    Cell cTarget = r.createCell(1);
    cTarget.setCellValue(1);
    PivotUtils.addCellValueTo(cSource, cTarget);
    // then
    Assertions.assertThat(cTarget.getNumericCellValue()).isEqualTo(1);
    // when numeric
    cSource = r.createCell(0);
    cTarget = r.createCell(1);
    cSource.setCellValue(1);
    cTarget.setCellValue(2);
    PivotUtils.addCellValueTo(cSource, cTarget);
    // then
    Assertions.assertThat(cTarget.getNumericCellValue()).isEqualTo(3);
    // when mixed: adding ignored
    cSource.setCellValue(1);
    cTarget.setCellValue("b");
    PivotUtils.addCellValueTo(cSource, cTarget);
    // then
    Assertions.assertThat(cTarget.getStringCellValue()).isEqualTo("b");
    // when boolean: adding ignored
    cSource.setCellValue(true);
    cTarget.setCellValue(false);
    PivotUtils.addCellValueTo(cSource, cTarget);
    // then
    Assertions.assertThat(cTarget.getBooleanCellValue()).isEqualTo(false);
}