code: def test_oncolor(util):
      # It doesn't need to be a ColorClip
      clip = ColorClip(size=(100, 60), color=(255, 0, 0), duration=0.5)
      on_color_clip = clip.on_color(size=(200, 160), color=(0, 0, 255))
      location = os.path.join(util.TMP_DIR, "oncolor.mp4")
      on_color_clip.write_videofile(location, fps=24)
      assert os.path.isfile(location)
  
      # test constructor with default arguments
      clip = ColorClip(size=(100, 60), is_mask=True)
      clip = ColorClip(size=(100, 60), is_mask=False)
  
      # negative test
      with pytest.raises(Exception):
          clip = ColorClip(
              size=(100, 60), color=(255, 0, 0), is_mask=True
          )
  
      with pytest.raises(Exception):
          clip = ColorClip(size=(100, 60), color=0.4, ismask=False)
  
      with pytest.raises(Exception):
          clip = ColorClip(size=(100, 60), color="black")
  
imports: import copy
  import os
  import numpy
  from PIL import Image
  import pytest
  from moviepy.audio.AudioClip import AudioClip
  from moviepy.audio.io.AudioFileClip import AudioFileClip
  from moviepy.tools import convert_to_seconds
  from moviepy.video.compositing.CompositeVideoClip import CompositeVideoClip
  from moviepy.video.fx.mask_color import mask_color
  from moviepy.video.fx.multiply_speed import multiply_speed
  from moviepy.video.io.VideoFileClip import VideoFileClip
  from moviepy.video.VideoClip import BitmapClip, ColorClip, ImageClip, VideoClip
label_desc: Use image node_id 20 for calling a global function with example usage: test_oncolor(util) without return types