code: def test_setimage(self):
      buf = BytesIO(b"\x00" * 255)
  
      im = MockImageFile(buf)
  
      im.load()
  
      assert self.decoder.state.xoff == xoff
      assert self.decoder.state.yoff == yoff
      assert self.decoder.state.xsize == xsize
      assert self.decoder.state.ysize == ysize
  
      with pytest.raises(ValueError):
          self.decoder.set_as_raw(b"\x00")
  
imports: from __future__ import annotations
  from io import BytesIO
  import pytest
  from PIL import BmpImagePlugin, EpsImagePlugin, Image, ImageFile, UnidentifiedImageError, _binary, features
  from .helper import assert_image, assert_image_equal, assert_image_similar, fromstring, hopper, skip_unless_feature, tostring
label_desc: Use image node_id 1 for calling the TestPyDecoder obj's underlying member method code with example usage: obj.test_setimage() without return types