code: def test_open():
      # Act
      with Image.open(TEST_FILE) as im:
          # Assert
          assert im.format == "XVThumb"
  
          # Create a Hopper image with a similar XV palette
          im_hopper = hopper().quantize(palette=im)
          assert_image_similar(im, im_hopper, 9)
  
imports: import pytest
  from PIL import Image, XVThumbImagePlugin
  from .helper import assert_image_similar, hopper
label_desc: Use image node_id 1 for calling a global function with example usage: test_open() without return types