code: def test_centers_to_edges():
      """Test centers_to_edges."""
      assert_allclose(
          centers_to_edges([0, 1, 2])[0], [-0.5, 0.5, 1.5, 2.5]
      )
      assert_allclose(centers_to_edges([0])[0], [-0.001, 0.001])
      assert_allclose(centers_to_edges([1])[0], [0.999, 1.001])
      assert_allclose(centers_to_edges([1000])[0], [999.0, 1001.0])
  
imports: from pathlib import Path
  import matplotlib.pyplot
  import numpy
  import pytest
  from numpy.testing import assert_allclose
  from mne import read_evokeds
  from mne.epochs import Epochs
  from mne.event import read_events
  from mne.io import read_raw_fif
  from mne.viz import ClickableImage, add_background_image, mne_analyze_colormap
  from mne.viz.ui_events import ColormapRange, link, subscribe
  from mne.viz.utils import _compute_scalings, _fake_click, _fake_keypress, _fake_scroll, _get_color_list, _make_event_color_dict, _setup_vmin_vmax, _validate_if_list_of_axes, centers_to_edges, compare_fiff, concatenate_images
label_desc: Use image node_id 9 for calling a global function with example usage: test_centers_to_edges() without return types