And there is also special tests for dogs that will tell if they are dangerous or not.
There is no guarenteed "test" that will enable to tell what dog is dangerous and which dog isn't.

Most of what you said was confusing to me, and I didn't understand

It sounds as if you think everyone here is after a purebred dog??? Whenever I hear someone ask what breed they should get, every response comes out "mutt." and whenever someone asks where they should get one, everyone here says "shelter."

But the puppymills and breeders will never shut down/go out of business as long as people keep buying from them.
This also confused me??? People don't buy from puppymills, they buy from petshops that have puppymill puppies. Most don't understand where these pups come from, and you cant exactly blame uneducated people. Also, why would anyone want breeders to go out of business? I mean reputable ones of course. I understand the population problem, but good breeders are a good place to get healthy well-lined dogs