### Question:
Region implements Serializable, Comparable<Region> { public static Region valueOf(@NonNull String name) throws IllegalArgumentException { Optional<Region> maybeRegion = getRegionAndRegisterIfNecessary(name); if (!maybeRegion.isPresent()) { throw new IllegalArgumentException("Unknown region " + name); } return maybeRegion.get(); } private  Region(
            @NonNull String regionId, @NonNull Optional<String> regionCode, @NonNull Realm realm); String getRegionCode(); Optional<String> getEndpoint(Service service); int compareTo(Region other); @Override // For backward compatibility maintain the enum toString behavior String toString(); static Region[] values(); static Region valueOf(@NonNull String name); static String formatDefaultRegionEndpoint(Service service, Region region); static String formatDefaultRegionEndpoint(Service service, String regionId); static Region fromRegionId(String regionId); static Region fromRegionCode(String regionCode); static Region fromRegionCodeOrId(String regionCodeOrId); static Region register(@NonNull String regionId, @NonNull final Realm realm); static Region register(
            @NonNull String regionId, @NonNull final Realm realm, String regionCode); static void setInstanceMetadataServiceClientConfig(ClientConfig clientConfig); static void enableInstanceMetadataService(); static void skipInstanceMetadataService(); static boolean registerFromInstanceMetadataService(); static final Region AP_CHUNCHEON_1; static final Region AP_MELBOURNE_1; static final Region AP_HYDERABAD_1; static final Region AP_MUMBAI_1; static final Region AP_OSAKA_1; static final Region AP_SEOUL_1; static final Region AP_SYDNEY_1; static final Region AP_TOKYO_1; static final Region CA_MONTREAL_1; static final Region CA_TORONTO_1; static final Region EU_AMSTERDAM_1; static final Region EU_FRANKFURT_1; static final Region EU_ZURICH_1; static final Region ME_JEDDAH_1; static final Region ME_DUBAI_1; static final Region SA_SAOPAULO_1; static final Region UK_LONDON_1; static final Region US_ASHBURN_1; static final Region US_PHOENIX_1; static final Region US_SANJOSE_1; static final Region US_LANGLEY_1; static final Region US_LUKE_1; static final Region US_GOV_ASHBURN_1; static final Region US_GOV_CHICAGO_1; static final Region US_GOV_PHOENIX_1; static final Region UK_GOV_LONDON_1; static final Region UK_GOV_CARDIFF_1; static final Region AP_CHIYODA_1; }### Answer:
@Test public void validRegionName() { assertSame(Region.CA_TORONTO_1, Region.valueOf("CA_TORONTO_1")); assertSame(Region.US_PHOENIX_1, Region.valueOf("US_PHOENIX_1")); }
@Test(timeout = 10000, expected = IllegalArgumentException.class) public void testValueOf() { Region.setInstanceMetadataServiceClientConfig( new ClientConfig() .property(ClientProperties.CONNECT_TIMEOUT, 1000) .property(ClientProperties.READ_TIMEOUT, 5000)); Region.valueOf("unknown"); }