This would be hilarious if it were true. Sadly, it's not. Test came into English from Latin, not Greek. The Greek for testicle is a whole other root parastatai.

Actually, it's still funny, but the setup insisting on this being the real history if the word is unnecessary and may mislead someone who repeats it as fact and embarrasses themselves, so just set it up as "it would be funny if" or something.

Citing some sources:

etymology of test

etymology of testicle