old_contents: import utime
  try:
      utime.sleep_ms
  except AttributeError:
      print("SKIP")
      raise SystemExit
  
  utime.sleep_ms(1)
  utime.sleep_us(1)
  print(utime.ticks_diff(utime.ticks_ms(), utime.ticks_ms()) <= 1)
  print(utime.ticks_diff(utime.ticks_us(), utime.ticks_us()) <= 500)
  
  # ticks_cpu may not be implemented, at least make sure it doesn't decrease
  print(utime.ticks_diff(utime.ticks_cpu(), utime.ticks_cpu()) >= 0)
  
new_contents: import utime
  try:
      utime.sleep_ms
  except AttributeError:
      print("SKIP")
      raise SystemExit
  
  utime.sleep_ms(1)
  utime.sleep_us(1)
  
  t0 = utime.ticks_ms()
  t1 = utime.ticks_ms()
  print(0 <= utime.ticks_diff(t1, t0) <= 1)
  
  t0 = utime.ticks_us()
  t1 = utime.ticks_us()
  print(0 <= utime.ticks_diff(t1, t0) <= 500)
  
  # ticks_cpu may not be implemented, at least make sure it doesn't decrease
  t0 = utime.ticks_cpu()
  t1 = utime.ticks_cpu()
  print(utime.ticks_diff(t1, t0) >= 0)
  
subject: Fix ticks tests, ticks_diff args are reversed.