@Bleu
There’s at least a day of setting up, and a day of packing everything up, as well as the organisation of getting the track into a state where they can run the car safely. Assuming there is a full day testing, that’s three days of time spent just on giving Ricciardo more experience in the car, which he probably doesn’t need.
In-season testing, like they used to do would involve a separate test team that could test without interfering with the logistics of the race team. Ferrari can do “filming days” quite easily at Fiorano because there’s no travel involved, so there’s much less setup.