Test program to check every LEDs of your Unicorn HD HAT from @pimoroni

testpattern.py

#!/usr/bin/env python
import time
import unicornhathd

print("""Unicorn HAT HD: Test pattern

Press Ctrl+C to exit!
""")

try:
    while True:
      for x in range(0, 16):
        for y in range(0, 16):
          unicornhathd.set_pixel(x, y, 255, 0, 0)
      unicornhathd.show()
      time.sleep(2)
      for x in range(0, 16):
        for y in range(0, 16):
          unicornhathd.set_pixel(x, y, 0, 255, 0)
      unicornhathd.show()
      time.sleep(2)
      for x in range(0, 16):
        for y in range(0, 16):
          unicornhathd.set_pixel(x, y, 0, 0, 255)
      unicornhathd.show()
      time.sleep(2)
      for x in range(0, 16):
        for y in range(0, 16):
          unicornhathd.set_pixel(x, y, 255, 255, 255)
      unicornhathd.show()
      time.sleep(2)

except KeyboardInterrupt:
    unicornhathd.off()