code: def test_canned_write_custom_template(canned_write_client):
      response = canned_write_client.get("/data/update_name")
      assert response.status == 200
      assert "!!!CUSTOM_UPDATE_NAME_TEMPLATE!!!" in response.text
      assert (
          "<!-- Templates considered: *query-data-update_name.html, query-data.html, query.html -->"
          in response.text
      )
      # And test for link rel=alternate while we're here:
      assert (
          '<link rel="alternate" type="application/json+datasette" href="http://localhost/data/update_name.json">'
          in response.text
      )
      assert (
          response.headers["link"]
          == 'http://localhost/data/update_name.json; rel="alternate"; type="application/json+datasette"'
      )
  
imports: from bs4 import BeautifulSoup
  import json
  import pytest
  import re
  from .fixtures import make_app_client, app_client
label_desc: Use image node_id 21 for calling a global function with example usage: test_canned_write_custom_template(canned_write_client) without return types