Always make a bet with yourself about whether a test will pass or not
Kent Beck calls this "calling your shot"
Sometimes when you think that it will fail you'll be surprised when it doesn't.
Loosely related, and interesting:
Later in the film, there was a shot of Carnegie Mellon's CHIMP robot considering a simulation of its future actions. In effect, it was predicting what it expected it would be able to do, and running through it, much like an athlete might visualize a race beforehand. It was a real-time rendered 3D animation that also served to give the researchers insight into how CHIMP was thinking about its next movements.
At 53, the software shows where it would like to take a peek, and where it actually decided to take a peek.