code: def test_renderer(renderer, monkeypatch):
      """Test that renderers are available on demand."""
      backend = renderer.get_3d_backend()
      cmd = [
          sys.executable,
          "-uc",
          "import mne; mne.viz.create_3d_figure((800, 600), show=True); "
          "backend = mne.viz.get_3d_backend(); "
          "assert backend == %r, backend" % (backend,),
      ]
      monkeypatch.setenv("MNE_3D_BACKEND", backend)
      run_subprocess(cmd)
  
file_path: mne-python/mne/viz/backends/tests/test_renderer.py
imports: import os
  import platform
  import sys
  import numpy
  import pytest
  from mne.utils import run_subprocess
  from mne.viz import Figure3D, get_3d_backend, set_3d_backend
  from mne.viz.backends._utils import ALLOWED_QUIVER_MODES
  from mne.viz.backends.renderer import _get_renderer
  from mne.viz.backends.tests._utils import skips_if_not_pyvistaqt
label_desc: Use image node_id 5 for calling a global function with example usage: test_renderer(renderer, monkeypatch) without return types