code: def test_tab_jshost_custom():
      from pyecharts.globals import CurrentConfig
  
      default_host = CurrentConfig.ONLINE_HOST
      custom_host = "http://localhost:8888/assets/"
      CurrentConfig.ONLINE_HOST = custom_host
      bar = _create_bar()
      line = _create_line()
      tab = Tab().add(bar, "bar").add(line, "line")
      assert_equal(tab.js_host, custom_host)
      CurrentConfig.ONLINE_HOST = default_host
  
imports: from typing import Iterable
  from unittest.mock import patch
  from nose.tools import assert_equal, assert_in, assert_true
  from pyecharts import options
  from pyecharts.charts import Bar, Line, Tab
  from pyecharts.commons.utils import OrderedSet
  from pyecharts.components import Table
  from pyecharts.faker import Faker
  from pyecharts.globals import ThemeType
label_desc: Use image node_id 8 for calling a global function with example usage: test_tab_jshost_custom() without return types