docstr: Files with extensions NOT listed in app_static_file_handler.py
  `SAFE_APP_STATIC_FILE_EXTENSIONS` should have the `Content-Type` header value
  equals to `text-plain`.
docstr_tok: ["Files","with","extensions","NOT","listed","in","app_static_file_handler.py","`","SAFE_APP_STATIC_FILE_EXTENSIONS","`","should","have","the","`","Content-Type","`","header","value","equals","to","`","text-plain","`","."]
code: def test_static_files_200(self):
      """Files with extensions NOT listed in app_static_file_handler.py
      `SAFE_APP_STATIC_FILE_EXTENSIONS` should have the `Content-Type` header value
      equals to `text-plain`.
      """
      responses = [
          # self._filename is file without extension
          self.fetch(f"/app/static/{self._filename}"),
          # self._js_filename is file with '.js' extension
          self.fetch(f"/app/static/{self._js_filename}"),
          # self._symlink_inside_directory is symlink to
          # self._tmpfile (inside static directory)
          self.fetch(f"/app/static/{self._symlink_inside_directory}"),
      ]
      for r in responses:
          assert r.headers["Content-Type"] == "text/plain"
          assert r.headers["X-Content-Type-Options"] == "nosniff"
          assert r.code == 200
  
file_path: streamlit/lib/tests/streamlit/web/server/app_static_file_handler_test.py
imports: import os
  import tempfile
  from unittest.mock import MagicMock, patch
  import tornado.httpserver
  import tornado.testing
  import tornado.web
  import tornado.websocket
  from streamlit.web.server.app_static_file_handler import MAX_APP_STATIC_FILE_SIZE, AppStaticFileHandler
label_desc: Use image node_id 4 for calling the AppStaticFileHandlerTest obj's underlying member method code with example usage: obj.test_static_files_200() without return types