Well, If you can squat feet together, ass to ankle, and/or can sit in the bottom position of a pistol, you’re good. Or at Juggernaut there was an article on self assessment; basically it said that you have full ankle dorsiflexion if you can sit in a half kneeling position, 5 inches from the wall, and touch the wall with your kneecap: http://jtsstrength.com/articles/2014/02/05/self-assessments-worth-correcting-part-2-ankle-mobility/