new_contents: import numpy as np
  from numpy.testing import assert_array_equal
  from skimage.segmentation import find_boundaries, mark_boundaries
  
  
  def test_find_boundaries():
      image = np.zeros((10, 10))
      image[2:7, 2:7] = 1
  
      ref = np.array([[0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
                      [0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
                      [0, 0, 1, 1, 1, 1, 1, 1, 0, 0],
                      [0, 0, 1, 0, 0, 0, 0, 1, 0, 0],
                      [0, 0, 1, 0, 0, 0, 0, 1, 0, 0],
                      [0, 0, 1, 0, 0, 0, 0, 1, 0, 0],
                      [0, 0, 1, 0, 0, 0, 0, 1, 0, 0],
                      [0, 0, 1, 1, 1, 1, 1, 0, 0, 0],
                      [0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
                      [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]])
  
      result = find_boundaries(image)
      assert_array_equal(result, ref)
  
  
  def test_mark_boundaries():
      image = np.zeros((10, 10))
      label_image = np.zeros((10, 10))
      label_image[2:7, 2:7] = 1
  
      ref = np.array([[0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
                      [0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
                      [0, 0, 1, 1, 1, 1, 1, 1, 0, 0],
                      [0, 0, 1, 0, 0, 0, 0, 1, 0, 0],
                      [0, 0, 1, 0, 0, 0, 0, 1, 0, 0],
                      [0, 0, 1, 0, 0, 0, 0, 1, 0, 0],
                      [0, 0, 1, 0, 0, 0, 0, 1, 0, 0],
                      [0, 0, 1, 1, 1, 1, 1, 0, 0, 0],
                      [0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
                      [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]])
      result = mark_boundaries(image, label_image, color=(1, 1, 1)).mean(axis=2)
      assert_array_equal(result, ref)
  
      ref = np.array([[0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
                      [0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
                      [0, 0, 1, 1, 1, 1, 1, 1, 2, 0],
                      [0, 0, 1, 2, 2, 2, 2, 1, 2, 0],
                      [0, 0, 1, 2, 0, 0, 0, 1, 2, 0],
                      [0, 0, 1, 2, 0, 0, 0, 1, 2, 0],
                      [0, 0, 1, 2, 0, 0, 0, 1, 2, 0],
                      [0, 0, 1, 1, 1, 1, 1, 2, 2, 0],
                      [0, 0, 2, 2, 2, 2, 2, 2, 0, 0],
                      [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]])
      result = mark_boundaries(image, label_image, color=(1, 1, 1),
                               outline_color=(2, 2, 2)).mean(axis=2)
      assert_array_equal(result, ref)
  
  
  if __name__ == "__main__":
      np.testing.run_module_suite()
  
subject: Add test case for *_boundaries functions