code: def test_gradio_app():
      api_types = GradioApp.get_available_api_types()
      for api_type in api_types:
          app = GradioApp(api_type, model=dummy_model)
          assert app
  
      for api_type in api_types:
          app = GradioApp(
              api_type,
              model=dummy_model,
              preprocess_fn=lambda dummy: dummy,
              postprocess_fn=lambda dummy: dummy,
          )
          assert app
  
file_path: chitra/tests/serve/test_app.py
imports: import unittest.mock
  from unittest.mock import MagicMock
  import numpy
  import pytest
  from chitra.serve import GradioApp
  from chitra.serve import constants
label_desc: Use image node_id 4 for calling a global function with example usage: test_gradio_app() without return types