code: def test_open():
      # Act
      with Image.open(TEST_FILE) as im:
          # Assert
          assert im.format == "BUFR"
  
          # Dummy data from the stub
          assert im.mode == "F"
          assert im.size == (1, 1)
  
file_path: pillow/Tests/test_file_bufrstub.py
imports: from __future__ import annotations
  import pytest
  from PIL import BufrStubImagePlugin, Image
  from .helper import hopper
label_desc: Use image node_id 1 for calling a global function with example usage: test_open() without return types