An astronaut would be a fool not to test them under conditions as realistic to being at the ISS as possible.
No, an astronaut would be a fool to subject himself bodily to a highly risky test (the vacuum chamber environment is hazardous for reasons besides heat rejection) solely to validate a piece of equipment. NASA spends literally millions of dollars training each individual astronaut. They are not guinea pigs.
There should be post test videos for every vacuum chamber simulated-EVA.
You misunderstand. When NASA tests sublimators, they don't test them using human subjects. They don't run all-up EVA tests in vacuum chambers, with the highly trained astronauts, just to validate
equipment.
You really have absolutely no clue whatsoever what is involved in engineering test. How did you manage to get a degree?