### Question:
Config { public static String[] getIndexCleanupPattern() { String patternStr = !Strings.isNullOrEmpty(CRON_INDEX_CLEANUP_PATTERN) ? CRON_INDEX_CLEANUP_PATTERN : getEnvironmentVariable("CRON_INDEX_CLEANUP_PATTERN"); if (!Strings.isNullOrEmpty(patternStr)) { try { return patternStr.split(","); } catch (PatternSyntaxException ignored) { } } return new String[0]; }  static DeploymentEnvironment getDeploymentEnvironment(); static String getIndexerHostUrl(); static String getSearchHostUrl(); static String getStorageQueryRecordFoRConversionHostUrl(); static String getStorageQueryRecordHostUrl(); static int getStorageRecordsBatchSize(); static String getStorageSchemaHostUrl(); static String getEntitlementsHostUrl(); static String getEntitlementTargetAudience(); static String getIndexerQueueHost(); static String getElasticCredentialsDatastoreKind(); static String getElasticCredentialsDatastoreId(); static boolean isLocalEnvironment(); static boolean isPreP4d(); static boolean isPreDemo(); static String getSearchRedisHost(); static int getSearchRedisPort(); static int getSchemaCacheExpiration(); static int getIndexCacheExpiration(); static int getKindsCacheExpiration(); static int getKindsRedisDataBase(); static int getAttributesCacheExpiration(); static int getElasticCacheExpiration(); static int getCursorCacheExpiration(); static String getGoogleCloudProjectId(); static String getDeployedServiceId(); static String getDeployedVersionId(); static String getElasticServerAddress(); static String getElasticClusterName(); static String getKmsRing(); static String getKmsKey(); static String getGoogleAudiences(); static String[] getIndexCleanupPattern(); static String[] getIndexCleanupTenants(); static int getIndexCleanupThresholdDays(); static int getEmptyIndexCleanupThresholdDays(); static final Boolean isSmartSearchCcsDisabled(); static Config Instance();  }### Answer:
@Test public void try_get_invalid_pattern() { System.setProperty("CRON_INDEX_CLEANUP_PATTERN", ""); String[] result = Config.getIndexCleanupPattern(); assertEquals(result.length, 0); System.setProperty("CRON_INDEX_CLEANUP_PATTERN", "blah;fdjo"); result = Config.getIndexCleanupPattern(); assertEquals(result.length, 1); System.setProperty("CRON_INDEX_CLEANUP_PATTERN", "-testindex*,-testquery*,-testcursor*"); result = Config.getIndexCleanupPattern(); assertEquals(result.length, 3); }