You can test your PostgreSQL resource hierarchy by initiating a manual switchover. This will simulate a failover of a resource instance from the primary server to the backup server.
Select Edit, then Resource, then In Service. For example, an In Service request executed on a backup server causes the application hierarchy to be taken out of service on the primary server and placed in service on the backup server. At this point, the original backup server is now the primary server and the original primary server has now become the backup server.
If you execute the Out of Service request, the application is taken out of service without bringing it in service on the other server.