@Test
public void testNullIP() throws IOException {

  String[] ips = {"10.119.103.112", "10.221.102.0/23"};
  createFileWithEntries ("ips.txt", ips);
  IPList ipList = new FileBasedIPList("ips.txt");
  assertFalse ("Null Ip is in the list",
      ipList.isIn(null));
}