xUnit general repository testing of add, update, delete

Is it worth unit testing the repository add, update or delete methods, please?

public void Update(TEntity entity)
{
    dbSet.Update(entity);
}

and usage:

UnitOfWork.NeakReports.Update(neakReport);

I ask because everything is moqed so I do not know if it is a must then how.

You can think about unit testing as a safety net.

So, the answer highly depends on what sort of safety net do you want to have, like:

1. do not alter the input rather pass it as it is to the underlying component
2. wrapper calls the right method (wrapper's Update should not call wrapped's Delete)
3. wrapper calls only the expected method on the dependency and nothing else ...

In other words if there is a chance in the future that this thin wrapper become thicker then you want to make sure it happens by breaking some test(s). If a code can sneak in without notice then it can cause harm.

Your level of paranoia will determine how much test is enough :)