Test marketing can indeed be that simple.
But practically never is, believe me...
This was actually before my ad career started but it's one of those things that has stuck with me all through it. I lived in Wichita when Pizza Hut (then based there) created the personal pan pizza with the five minute guarantee. And after I had my first one, I was surveyed about it, by a young woman using this electronic pad to record the answers. And after about ten questions I said to her, "All your questions have to do with how fast the service was. Don't you want to ask me if I thought it tasted good?"
She sort of scanned her device and then looked at me helplessly, "There's nowhere to put that in."
Ever since, I've had a high degree of skepticism toward research, recognizing that the answers you get are in large part a function of what questions you ask. And whenever I can, I try to leave a large area for the person to say WHATEVER they want to say to the company, with no guidelines, and have spent hours reading the feedback we got that way.
P.S. Speaking of Wendy's, one of their humorous commercials some years back made fun of excessive product research, and if you looked at the background, you saw that the research lab had a sign up which read:
RESEARCH PROVES
RESEARCH WORKS
Says it all.