private int mod(final int dividend) {
        int result = dividend % 100;
        return result >= 0 ? result : 100 + result;
    }
@Test
    public void testMod() throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
        Method method = countSampler.getClass().getDeclaredMethod("mod", int.class);
        method.setAccessible(true);
        int res = (int) method.invoke(countSampler, 1);
        Assertions.assertEquals(res, 1);
    }