code: def test_plot_topo_single_ch():
      """Test single channel topoplot with time cursor."""
      evoked = _get_epochs().average()
      evoked2 = evoked.copy()
      # test plotting several evokeds on different time grids
      evoked.crop(-0.19, 0)
      evoked2.crop(0.05, 0.19)
      fig = plot_evoked_topo([evoked, evoked2], background_color="w")
      # test status bar message
      ax = plt.gca()
      assert "MEG 0113" in ax.format_coord(0.065, 0.63)
      num_figures_before = len(plt.get_fignums())
      _fake_click(fig, fig.axes[0], (0.08, 0.65))
      assert num_figures_before + 1 == len(plt.get_fignums())
      fig = plt.gcf()
      ax = plt.gca()
      _fake_click(
          fig, ax, (0.5, 0.5), kind="motion"
      )  # cursor should appear
      assert isinstance(ax._cursorline, matplotlib.lines.Line2D)
      _fake_click(
          fig, ax, (1.5, 1.5), kind="motion"
      )  # cursor should disappear
      assert ax._cursorline is None
      plt.close("all")
  
imports: from collections import namedtuple
  from pathlib import Path
  import matplotlib
  import matplotlib.pyplot
  import numpy
  import pytest
  from mne import Epochs, compute_proj_evoked, read_cov, read_events
  from mne.channels import read_layout
  from mne.io import read_raw_fif
  from mne.time_frequency.tfr import AverageTFR
  from mne.utils import _record_warnings
  from mne.viz import _get_presser, mne_analyze_colormap, plot_evoked_topo, plot_topo_image_epochs
  from mne.viz.evoked import _line_plot_onselect
  from mne.viz.topo import _imshow_tfr, _plot_update_evoked_topo_proj, iter_topography
  from mne.viz.utils import _fake_click
label_desc: Use image node_id 8 for calling a global function with example usage: test_plot_topo_single_ch() without return types