Besides Apollo 12 also fulfilling the goal, just what was there left to test after Apollo 10? Aside from the unmanned flights that tested the CSM, Saturn V and LM, the previous manned flights did the same, with Apollo 10 doing literally everything but land, even being intentionally short fuelled so the astronauts couldn't get any funny ideas. The only thing to test fully was the actual landing, which you can't do without, well, landing.