code: def test_abstract():
      """Test app abstract template"""
      app = BaseApplicationBackend()
      for fun in (
          app._vispy_get_backend_name,
          app._vispy_process_events,
          app._vispy_run,
          app._vispy_quit,
      ):
          assert_raises(NotImplementedError, fun)
  
imports: import sys
  from collections import namedtuple
  from io import StringIO
  from time import sleep
  import gc
  import numpy
  from numpy.testing import assert_array_equal
  import pytest
  from vispy.app import use_app, Canvas, Timer, MouseEvent, KeyEvent
  from vispy.app.base import BaseApplicationBackend
  from vispy.testing import requires_application, SkipTest, assert_is, assert_in, run_tests_if_main, assert_equal, assert_true, assert_raises, IS_TRAVIS_CI
  from vispy.util import keys, use_log_level
  from vispy.gloo.program import Program, VertexBuffer, IndexBuffer
  from vispy.gloo.util import _screenshot
  from vispy.gloo import gl
label_desc: Use image node_id 11 for calling a global function with example usage: test_abstract() without return types