One of the steps for developing a cure in the "Lab challenge" is to test it. To do it a card of the cure color must be put on the test space and one disease cube of the color can be removed from any city.
Is it allowed to test a single cure multiple times? This would make it possible to treat the disease in a far away city (and reducing the number of city cards available for the cure).
I cannot find anything about it in the rules.