The answer is: Isolate the randomness.
You can check this example from Dave Farley where isolated Time: https://www.youtube.com/watch?v=SuDIYk9GBpE&t=1872s
Separate the randomly sorting behavior from the displaying and from the entity definition, using polymorphism.
Then you can validate each one of these parts in isolation:
When you want to validate ...
TLDR; Test randomness at the unit level using a Chi Test and then verify at the system level that the values properly propagate from the unit to the system.
By random you probably mean uniform distribution, that each value from a list have the same probability to be chosen.
To decide if something is uniformly distributed and have a meaningful result you need ...