I really only need to send an "on" or an "off" signal to the trinket somehow. I figured I'd ask here to see if someone might have some insight. HIDSerial never detects my trinket, and believe me, I've fiddled with both of them for hours (including downgrading gcc-avr just so it can recognize the -assembler-with-cpp flag, which is apparently just not there in the newest version). Adafruit admits that they've never tried the TrinketFakeUsbSerial on Linux (we do use linux at work), and I can't get it work for the life of me. I've tried the two "simple" solutions provided by Adafruit - the TrinketFakeUsbSerial, and HIDSerial.
#Adafruit trinket pins serial
Unfortunately, I didn't know that the trinket doesn't support serial communication like that. I got all of this working pretty easily on the UNO - I simply send a 1 over serial if the test suite is failing, and a 0 if it's not. I bought an Adafruit Trinket thinking it would be perfect for the project, since I really only need 3 GPIO pins (one for a green LED that will be on when the test suite isn't failing), one for the red LED, and one for the buzzer.