testWhileIdle属性在版本1.1.5中是无效的吗？

测试发现只要是开启了timeBetweenEvictionRunsMillis与minEvictableIdleTimeMillis，空闲连接在超过后者时就会关闭，无论testWhileIdle是true还是false,这个属性的意思与DBCP不一样吗？还是这个属性就是没用？

Start by reproducing the reported behavior in Druid 1.1.5 with timeBetweenEvictionRunsMillis, minEvictableIdleTimeMillis, and both values of testWhileIdle. Trace the idle-connection eviction entry point and compare the observed semantics with the intended behavior; done means the behavior is clarified and covered by an appropriate test or documentation update.

Written by the indexing model from the issue text.