When I set-up a MySQL HA environment for customers I usually do some final failover tests after configuring the whole beast.
To check if the application behaves like expected I always run my little test application (test.sh) from the server(s) where the customers application runs. It displays "graphically" how the application behaves and you can show to the customer immediately what is going on...
Make sure, that you point it to the virtual IP (VIP) or the load balancer (LB).
