### Question:
IpTree { public void add(String ip) { String[] ipNumbers = ip.split("\\."); NumberNode node = root; for (String number : ipNumbers) node = node.createOrGetChildNumber(number); }  void add(String ip); boolean containsIp(String ip);  }### Answer:
@Test public void level4StarIpTree() { ipTree.add("10.20.30.*"); assertIpTreeContainsIp(ipTree, "10.20.30", 0, 255, true); }