any component that requires breaking into a engine fluid system, be it fuel or oil require engine run leak checks. fuel system component changes often require a high power leak check, due to increased fuel flow at higher engine speeds. oil px switches may also need a higher power run, to check for correct indication through the specified range.
in the case of n1 and n2 probes, engine runs are required incase the component is fail on fit, or, to indicate if the probe was infact at fault (as fadec harnesses are often to blame, as i have found out many times)
most airports allow engine runs at grnd idle power on stand for maintenance, leak and function checks etc.