code: def test_es2():
      """es2 backend should have all ES 2.0 names. No more, no less."""
      # Import. Install a dummy lib so that at least we can import es2.
      try:
          from vispy.gloo.gl import es2  # noqa
      except Exception:
          import ctypes
  
          ctypes.TEST_DLL = _DummyObject()
      from vispy.gloo.gl import es2  # noqa
  
      # Test
      _test_function_names(es2)
      _test_constant_names(es2)
  
file_path: vispy/vispy/gloo/gl/tests/test_names.py
imports: from vispy.testing import requires_pyopengl
  from vispy.gloo import gl
  from vispy.testing import run_tests_if_main
label_desc: Use image node_id 5 for calling a global function with example usage: test_es2() without return types