### Question:
IdUtils { public static String makeSnRandom() { return makeSn() + RandomStringUtils.randomNumeric(3); }  static String makeUUID(); static String makeID(String bizCode); static String makeID(String bizCode, String serverId); static String makeSn(); static String makeSnRandom();  }### Answer:
@Test public void testMakeSnRandom() { String s = IdUtils.makeSnRandom(); System.out.println(s); Assertions.assertEquals(20, s.length()); }