Until an AI does that, it won't be able to pass a Turing test.
So many people I know believe that AI has already passed the Turing test. What's weird is that a lot of them are managers and should understand that never getting an "I don't know" means something ain't right.
AI passed the Turing Test empirically long ago. Further and more practically, they consistently convince millions of people that they are a real person with real intentions all the time, every day.
They are so convincing that an emergent property of the Turing Test is also being shown: that real humans are called bots by people that genuinely believe the other is a bot.
The standard 3-person Turing test with 2 people talking and a third observing and trying to decide which is a computer, if any, has been summarily defeated.