The fullback penned terms on Friday, now being in his second year with Wolves after joining from Manchester City.
Wolves academy manager Jon Hunter-Barrett said: “Testimony’s been rewarded with a contract after being a steady performer for the under-18s and has been in the team quite a lot over the last two years.
“His strengths are his techniques and ball management – he’s able to really manage the ball under pressure and he’s a consistent member of the group in terms of his personality and work ethic as a player.
“Sometimes as a full-back, the hard work can go unnoticed and particularly with the type of role Tess played as a low full-back.
“These types of players can sometimes go under the radar and people might not see them as much, but Testimony has been very consistent."