Google may be your friend , but unfortunately it does not always match conditions in the real world.
UV trip is relatively easy to test on most generators while the machine is running.- if the machine has voltage trim or has the breaker easily adjustable settings.
The overcurrent trips are more complicated and would usually be carried out at the special survey by shore contractors.
I notice that some of the links given specify "primary injection testing" - That is injecting the full fault current though the main terminals of the breaker- We are potentially talking large currents here and would be quite a specialised operation to do safely. I. would imagine that this would only be done once- when the breaker is new at the manufacturers workshop.
For later tests, it would be more practical to do the secondary injection testing.
In the ACB , usually a current transformer converts the main current into a lower signal current to operate the trip mechanism. I have seen this done once in a dry dock in Nagasaki. With the breaker racked out, but the control supply connected, the shore electricians connected up a special power supply to the trip unit and tested the various trips, i.e short time , long time. Unfortunately as is usual in a dry dock I was extremely busy and didn't get time to see and understand as much of the process as I would have liked, plus the electricians couldn't speak a word of english so they couldnt tell me much anyhow.
Later, I was class surveyor for a while. In my area there were no big drydocks so the only special surveys I did was on small tugs and work boats.
The class rules specified testing of the breakers but didnt go into details- instead referencing an IEE publication, which you cant get for free and my office wouldnt pay for ( one of the reasons I am no longer a class surveyor- but thats a long story).
On one survey on a tug, the local electricians said they knew how to do it and they mucked around all day with a home made current injector made out of a welder, but in the end - they couldnt do it.
The breakers ended up being removed and sent to a specialist work shop ashore . The owner complained much about the cost- apperently no other surveyor had ever asked him to do this before.
So to cut a long story short, in my opinion, it is only something you would do at the five year special survey, hopefully when you are in a dry dock, and you would contract the job to specialist electrical contractors, but you would still need to oversee them to ensure that they know what they are doing. As in all things , when all else fails read the instructions!, i.e in this case manufacturers manual and or recommendations.