code: def test_polygon():
      polygon = [(10, 10), (10, 20), (20, 20)]
      canvas = np.zeros((40, 40), np.bool_)
      fill_polygon(polygon, canvas)
      assert canvas.sum() == (10 * 10 + 10) / 2
      canvas2 = canvas.copy()
      fill_polygon([], canvas2)
      assert np.all(canvas == canvas2)
  
file_path: mahotas/mahotas/tests/test_polygon.py
imports: import numpy
  import mahotas
  import mahotas.polygon
  from mahotas.polygon import fill_polygon, fill_convexhull
  import pytest
label_desc: Use image node_id 1 for calling a global function with example usage: test_polygon() without return types