What is testing?

I've gotten far storyline wise but I haven't look at much else so there's still a lot of things about this site that I don't quite get.

Well testing could mean afew things, but I think you mean genetic testing. A large part of sylestia as a game and community is about breeding pets, and like with real animals, they have genetics. Each pet will have 6 gene slots, 3 of which are genes and 3 are mutations. If a pet have a a gene/mutation or trait, it can be visible, in which case it will show automatically on the pet and on its profile. However some traits are carried, meaning they do not show on that pet but may show on its offspring if bred properly. The only way to see carried genes (and which form of the gene it carries) is to get it tested. This can be done with genetic testing kits which can be bought with diamonds (and these kits can be used as many times as you want) or with lesser testing kits which only work once. If you don't have either of these, many people on the site offer free testing :)

Thank you!
That was really helpful