And who gets to decide that test? People like him.
It is not a good idea at all. It's also very eugenicsy and racist etc as it would invariably lead to marginalised groups being disenfranchised and prevented from voting due to systemic inequalities.
Right and how do you ensure people are educated in a way that works for the entire population in a system like it exists currently? Who controls access to accurate information and equal opportunities to learn?
Unless you personally are going to start lobbying, funding public education that isn't biased, help lift folks out of poverty, etc etc then sadly this kind of 'plan' is doomed to fail from the start.
I get the despair and desire to cling to ideas like this, but the system is stacked against your ideas and the people who need help the most in order to fully understand and interact with a system like this.
In order to achieve the best outcome all these systems need to be done away with, and in order to do that you need to build dual power, subvert existing power structures and stop seeing anybody but fascists and those in power as the enemy.
Most people are just struggling to get by day to day and your energy and anger would be better put into helping them directly or in groups who hold true love and care in their hearts and actions than preventing them from voting or saying they need to be 'educated' without explaining how or what that means.