### Question:
Hosts { public static boolean isValidIp(String ip) { return ip != null && (parseV4(ip) != null || parseV6(ip) != null); } Hosts(Context context, String name); @Nullable InetAddress get(String host); boolean put(String host, String ip); void delete(String host); List<Pair<String, String>> getAll(); @Nullable static InetAddress toInetAddress(String host, String ip); static boolean isValidHost(String host); static boolean isValidIp(String ip);  }### Answer:
@Test public void testIsValidIp() { assertTrue(Hosts.isValidIp("127.0.0.1")); assertTrue(Hosts.isValidIp("0.0.0.0")); assertFalse(Hosts.isValidIp("324.0.0.1")); assertFalse(Hosts.isValidIp("127.0.0.")); assertFalse(Hosts.isValidIp("127.0.0")); assertFalse(Hosts.isValidIp("-1.0.0")); assertFalse(Hosts.isValidIp("")); assertFalse(Hosts.isValidIp(null)); }