Has anyone ever done a DNA test on their dog?

Just curious, one of my dogs is a mix from a shelter, so we have no idea what he is except a little bit border collie. I don't think I would ever do it but I was wondering if anyone else has, it seems interesting to me that you could find out that kind of thing.
I posted pics, I wasn't going to but why not I guess.

And I did check around, it's like 0 and I don't care so like I said I wouldn't do it. Just wondering if anyone else has, geeeeez.

We adapted two dogs from the kennel over two years ago and love them so much but we are curious what breeds they have in them. We have heard of the dog DNA testing but do not know where to get that done at, if anyone has a link that would be great!
We would like to know a little bit more detailed so we can know what to watch out for in the future for medical reasons to know what to watch out for in the future. We dont mind spending the money and would just like to look into it.
We have been to the vets but our dogs are very unique and they say they really arent sure...but they are very healthy!