docstr: URLs should be formatted correctly, and have the expected extension.
docstr_tok: ["URLs","should","be","formatted","correctly",",","and","have","the","expected","extension","."]
code: def test_get_url(self, mimetype, extension):
      """URLs should be formatted correctly, and have the expected extension."""
      file_id = self.storage.load_and_get_id(
          b"mock_bytes", mimetype=mimetype, kind=MediaFileKind.MEDIA
      )
      url = self.storage.get_url(file_id)
      self.assertEqual(f"/mock/media/{file_id}{extension}", url)
  
imports: import unittest
  from unittest import mock
  from unittest.mock import MagicMock, mock_open
  from parameterized import parameterized
  from streamlit.runtime.media_file_storage import MediaFileKind, MediaFileStorageError
  from streamlit.runtime.memory_media_file_storage import MemoryFile, MemoryMediaFileStorage, get_extension_for_mimetype
label_desc: Use image node_id 6 for calling the MemoryMediaFileStorageTest obj's underlying member method code with example usage: obj.test_get_url(mimetype, extension) without return types