The generation of 'pt' in the validation phase

Hello, I have a question about the generation of 'pt' in the validation phase.
If I understand correctly, when MSA prepared the validation set, the function 'random_click' used in 'utils.py', will return pt from the foreground region of validation mask.
Does it make sense? Because in test stage, we have no idea about the ground truth masks. We can't generate pt then.