Just google it and loads of stuff comes up

I found this one seemed to test on the broadest range of skills from the 10 or so top results I tried

https://www.akademijaoxford.com/en/german-language-placement-test.php

www.deutsch-lernen.com/virtual/e_test_kurz_einleitung.php

Leave us a comment on how you did if you take any of the tests suggested. I'd be very interested. I am a bit nosy. ;-)

I searched right now and I found this one. There are two types of test.

https://www.deutsch-lernen.com/virtual/e_test_kurz_einleitung.php

There are other tests which cover all four abilities but I couldn't find one right now.

Edit: I found this one from Goethe Institut:

https://www.goethe.de/en/m/spr/kup/tsd.html