Is there a list of all the tests freelancers can take on Upwork? Do the freelancers have to pay for the tests? Do you ever ask an applicant to complete one of the tests to help with your decision and finding the best applicant?
On your main page (my tab calls it 'My Job Feed,' there's a link along the top called Tests, right next to My Stats. There are a lot of choices there. You should also change your image to a picture of you per Upwork rules. Good luck!
Upwork skill tests are free of charge and if you feel like it would help you make a decision, you can ask a freelance to complete a certain test to showcase their skills.
Though why a skills test (Upwork or whatever site) set by other (often less qualified) freelancers should be better proof than a university degree, or a good work background with proven work experience and portfolio, is an unsolved mystery.