Why does cosmetics have to be tested before use?

Would you buy a perfume if you didn't know that it was going to definitely not have a risk of causing severe problems? If I gave you the choice of two perfumes which smelled the same, but one of them had been tested with no side effects and the other hadn't been tested at all, which would you choose?

By testing perfumes(on humans, nonetheless) you make sure that there is nothing in it which is harmful to humans