code: def test_event_data(self):
      with gr.Blocks() as demo:
          text = gr.Textbox()
          gallery = gr.Gallery()
  
          def fn_img_index(evt: gr.SelectData):
              return evt.index
  
          gallery.select(fn_img_index, None, text)
  
      app, _, _ = demo.launch(prevent_thread_lock=True)
      client = TestClient(app)
  
      resp = client.post(
          f"{demo.local_url}run/predict",
          json={
              "fn_index": 0,
              "data": [],
              "event_data": {"index": 1, "value": None},
          },
      )
      assert resp.status_code == 200
      assert resp.json()["data"][0] == "1"
  
file_path: gradio/test/test_events.py
imports: import ast
  import inspect
  from pathlib import Path
  import pytest
  from fastapi.testclient import TestClient
  import gradio
label_desc: Use image node_id 2 for calling the TestEvent obj's underlying member method code with example usage: obj.test_event_data() and returns: evt