Random selection Daml

Does anyone know how to simulate a random selection in Daml? My understanding is that I cannot make non-deterministic choices in Daml (I should call an external Oracle and ask for an index), but for testing purposes I should be able to simulate a random selection within the software.

Is that correct? Could someone please help? I cannot find any function such as "choose" "shuffle" or any other related function.

Could someone point me in the right direction please?

Any help would be very much appreciated!!!