@Test
public void testDigits() throws Exception {

    assertEquals(1, DecimalStringSplit.digits(0));
    assertEquals(1, DecimalStringSplit.digits(1));
    assertEquals(1, DecimalStringSplit.digits(9));
    assertEquals(2, DecimalStringSplit.digits(10));
    assertEquals(2, DecimalStringSplit.digits(99));
    assertEquals(3, DecimalStringSplit.digits(100));
    assertEquals(6, DecimalStringSplit.digits(100000));
    assertEquals(1, DecimalStringSplit.digits(-1));
}