What is N testing? (In 100 Words or Less)

During summer, my favorite time of day was when the ice cream truck would drive on our street. Usually, I didn't know what I wanted. If I had saved enough money, I'd order a push-up (am I dating myself, or is this still offered?), the rocket...

What is N testing? (In 100 Words or Less)

During summer, my favorite time of day was when the ice cream truck would drive on our street.

Usually, I didn't know what I wanted. If I had saved enough money, I'd order a push-up (am I dating myself, or is this still offered?), the rocket popsicle, and an ice cream sandwich.