Those who participate in formal testing.
The testies from dicks class were sweating under pressure.
A person or group of people who test a prototype design
The testies knew that the prototype parachute was going to be a massive success.
A description for one testicle
As i ran on the treadmill my testi brothers slapped against my sweaty groin!
Someone who is easy to set off or have very low amounts of patience. You could say something meant as a compliment and they'll flip out regardless.
Guy 1: Dude, ready the fuck up!
Guy 2: It's only been 5 seconds you testy fag.
1. The plural of "tests" or exams.
2. Any multiple of a timed evaluation.
"How did you do on all the testis"