@Test
public void testPower() {

    assertEquals(10_000, DigitUtils.DIV, "Value of DigitUtils.DIV was changed, must be always 10_000");
    assertEquals(0, DigitUtils.getPower(42).power7);
    assertEquals(42, DigitUtils.getPower(42).power4);
    assertEquals(1, DigitUtils.getPower(10042).power7);
    assertEquals(42, DigitUtils.getPower(10042).power4);
    assertEquals(100, DigitUtils.getPower(1009999).power7);
    assertEquals(9999, DigitUtils.getPower(1009999).power4);
}