code: def test_contour_line_start_on_corner_edge(split_collections):
      fig, ax = plt.subplots(figsize=(6, 5))
  
      x, y = np.meshgrid([0, 1, 2, 3, 4], [0, 1, 2])
      z = 1.2 - (x - 2) ** 2 + (y - 1) ** 2
      mask = np.zeros_like(z, dtype=bool)
      mask[1, 1] = mask[1, 3] = True
      z = np.ma.array(z, mask=mask)
  
      filled = ax.contourf(x, y, z, corner_mask=True)
      cbar = fig.colorbar(filled)
      lines = ax.contour(x, y, z, corner_mask=True, colors="k")
      cbar.add_lines(lines)
  
      _maybe_split_collections(split_collections)
  
imports: import datetime
  import platform
  import re
  from unittest import mock
  import contourpy
  import numpy
  from numpy.testing import assert_array_almost_equal, assert_array_almost_equal_nulp, assert_array_equal
  import matplotlib
  from matplotlib import pyplot, rc_context, ticker
  from matplotlib.colors import LogNorm, same_color
  import matplotlib.patches
  from matplotlib.testing.decorators import check_figures_equal, image_comparison
  import pytest
label_desc: Use image node_id 30 for calling a global function with example usage: test_contour_line_start_on_corner_edge(split_collections) without return types