Sometimes you want to see how your bike, or kit, or new piece of equipment will work on an ultra long ride, maybe a several days tour. The key word being see. When you only want to see, you don't necessarily want to have to suffer for long with the consequences. An test is meant to gather information; it needs to be a reasonable enough duration that you can test brand new and genuinely "experimental" equipment.
The other day two of us went on just such a ride, testing a handlebar/front rack on a singlespeed flat pedal rigid 26" MTB and a single, fully loaded, left, rear pannier on a steel Bianchi with moustache bars. Of course, we were carrying a bunch of unnecessary weight, just see. Oh yeah.... and it was hot because it's July, and we're in Texas. We did about 75 miles in 6 hours. Here's some of what it looked like.
Kona Unit, pre-ride at Shift Coffee
"I think I see some shade!"
So much water
Texans in their natural habitat.
Sara, I drank your Coke...