The phrase "real testament" refers to something that serves as genuine evidence or proof of something important or true. It is a reliable and trustworthy confirmation of information or beliefs. Full definition
The fact that Doty hasn't publicly blown his top is a real testament to his character. (fortune.com)
«We are very proud of the wines we produce and to receive the wide recognition we have this year is a real testament to the relentless energy and cumulative effort from vineyards to wineries then bottling. (accolade-wines.com)
The fact that I still remember how delicious it was is a real testament to just how good this simple tomato pie was. (jeanetteshealthyliving.com)