Repro

prop file like

org.infinispan.agroal.minSize=2
org.infinispan.agroal.maxSize=8
org.infinispan.agroal.initialSize=2
org.infinispan.agroal.acquisitionTimeout=PT5S
org.infinispan.agroal.validationTimeout=PT10S
org.infinispan.agroal.reapTimeout=PT5M
org.infinispan.agroal.jdbcUrl=jdbc:postgresql://postgres:5432/infinispan
org.infinispan.agroal.providerClassName=org.postgresql.Driver
org.infinispan.agroal.principal=postgres
org.infinispan.agroal.credential=postgres

then read properties from the props file (this is how Infinispan reads them)

dataSource = AgroalDataSource.from(new AgroalPropertiesReader(PROPERTIES_PREFIX).readProperties(propsFile));

Expected

validation occurs and WORKS on invalid connections 

Actual

validation occurs and ALWAYS succeeds even for faulted connections as the validator defaults to "empty" which always returns `isValid = true` and failed connections never leave the pool.

Workaround

Instead of validationTimeout, set up maxLifetime.

That way connections will be forcefully deleted from the pool regardless the fact they are closed or not, but at least there won't be an outage.

Proposal

Add the ability to parse validator from props, e.g.

org.infinispan.agroal.validator=default