@Test
    public void testGreater2PowersExponent() {
        logger.info("greater2PowersExponent");

        int[] number =    {0, 1,2, 3,4, 5,6,7,8, 9,10,11,12,13,14,15,16,17,18,19,20};
        int[] expResult = {0, 0,1, 2,2, 3,3,3,3, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5};

        for (int i = 0; i < number.length; i++) {
            logger.info("Trying "+i);
            int result = PowersHelper.greater2PowersExponent(number[i]);
            assertEquals(expResult[i], result);
        }
    }