code: def test_image_processor_to_json_string(self):
      image_processor = self.image_processing_class(
          **self.image_processor_dict
      )
      obj = json.loads(image_processor.to_json_string())
      for key, value in self.image_processor_dict.items():
          self.assertEqual(obj[key], value)
  
imports: import json
  import os
  import pathlib
  import tempfile
  from transformers import BatchFeature
  from transformers.image_utils import AnnotationFormat, AnnotionFormat
  from transformers.testing_utils import check_json_file_has_correct_format, require_torch, require_vision
  from transformers.utils import is_torch_available, is_vision_available
label_desc: Use image node_id 1 for calling the ImageProcessingTestMixin obj's underlying member method code with example usage: obj.test_image_processor_to_json_string() without return types