I'd tell your therapist how you'd like to say goodbye! I think if an ending ritual is important to you it's a good idea to make that happen.

I doubt your therapist is testing you- I can't imagine why a therapist would do such a thing. It would be a good idea to tell her how you would like things to be so she can make it so- you are paying her so it's important to be open about what will make you happy with her.