[Fretsource]

FRETQUIZ is a guitar-related music theory quiz, with help pages containing the theory you need to know for each of the two levels of difficulty (beginners & beyond). You answer 20 questions from a multiple choice selection and see your current score as you play.
There are over a hundred questions for each of the two levels of difficulty, so you can take the quiz more than once without seeing too many repeated questions.

There's also an option to exclude questions with standard notion as many guitarists learn guitar and music theory without learning standard notation.

Good luck