How not to fix Democracy

In The Guardian Dambisa Moyo proposes a test to improve the quality of the electorate:

"...why not give all voters a test of their knowledge? This would ensure minimum standards that should lead to higher-quality decision-making by the electorate."

However:

"Of course, such a system would be truly democratic only if everybody had a fair chance of casting their vote. It is vital that those with fewer life opportunities have their say, and we cannot have a system that is skewed against the worst educated..."

So the idea is a test of minimum standards that in some way is not biased against the worst educated? Or that we could only impose such a system once education has improved to the point where is is no longer needed?

Maybe we just need a test to improve the quality of Guardian opinion pieces.