Yes, I have come across the following tests to measure self-control of kids:
1. Marshmallow test: Walter Mischel, Stanford psychologist and colleagues developed the “marshmallow test” in the 1960s, which popularly known as a measure of willpower. The experiment gave preschoolers the option of either eating one mini-marshmallow right away or waiting 15 minutes to get two mini-marshmallows.
2. Academic diligence task: This test was created by Brian Galla and Angela Duckworth of the University of Pennsylvania, with Sidney D’Mello of the University of Notre Dame, as a better (and free) research tool for measuring self-control.
This new computer-based test offers students a choice between doing math or watching videos or playing a video game.