code: def test_open():
      # Act
      with Image.open(TEST_FILE) as im:
          # Assert
          assert im.format == "GRIB"
  
          # Dummy data from the stub
          assert im.mode == "F"
          assert im.size == (1, 1)
  
imports: import pytest
  from PIL import GribStubImagePlugin, 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