### Question:
Config { public static String[] getIndexCleanupTenants() { String patternStr = !Strings.isNullOrEmpty(CRON_INDEX_CLEANUP_TENANTS) ? CRON_INDEX_CLEANUP_TENANTS : getEnvironmentVariable("CRON_INDEX_CLEANUP_TENANTS"); 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_indexCleanUp_tenants() { System.setProperty("CRON_INDEX_CLEANUP_TENANTS", ""); String[] result = Config.getIndexCleanupTenants(); assertEquals(result.length, 0); System.setProperty("CRON_INDEX_CLEANUP_TENANTS", "tenant1;fdjo"); result = Config.getIndexCleanupTenants(); assertEquals(result.length, 1); System.setProperty("CRON_INDEX_CLEANUP_TENANTS", "tenant1,common"); result = Config.getIndexCleanupTenants(); assertEquals(result.length, 2); }