### Question:
HintManagerHolder { public static Optional<ShardingValue<?>> getDatabaseShardingValue(final ShardingKey shardingKey) { return isUseShardingHint() ? Optional.<ShardingValue<?>>fromNullable(HINT_MANAGER_HOLDER.get().getDatabaseShardingValue(shardingKey)) : Optional.<ShardingValue<?>>absent(); }  static void setHintManager(final HintManager hintManager); static boolean isUseShardingHint(); static Optional<ShardingValue<?>> getDatabaseShardingValue(final ShardingKey shardingKey); static Optional<ShardingValue<?>> getTableShardingValue(final ShardingKey shardingKey); static boolean isMasterRouteOnly(); static boolean isDatabaseShardingOnly(); static void clear(); static final String DB_TABLE_NAME; static final String DB_COLUMN_NAME; }### Answer:
@Test public void assertClear() { hintManager.addDatabaseShardingValue("logicTable", "shardingColumn", 1); hintManager.close(); assertFalse(HintManagerHolder.getDatabaseShardingValue(new ShardingKey("logicTable", "shardingColumn")).isPresent()); }