Possible Clues:

• Personality test? (Last 3 letters + ...)
• Security test to keep out bots
• Acronym for a challenge response test used to tell humans and computers apart
• Improve on tea, say, with more of it: that's a test for humanity
• Challenge-response test used to determine whether a user is human
• Computer test used in diagnostic: apt challenge
• Technology that I guess has outed me as a robot because I always get it wrong