old_contents: import numpy as np
  from numpy.testing import assert_array_equal
  from skimage.segmentation import clear_border
  
  
  def test_clear_border():
      image = np.array(
          [[0, 0, 0, 0, 0, 0, 0, 1, 0],
           [0, 0, 0, 0, 1, 0, 0, 0, 0],
           [1, 0, 0, 1, 0, 1, 0, 0, 0],
           [0, 0, 1, 1, 1, 1, 1, 0, 0],
           [0, 1, 1, 1, 1, 1, 1, 1, 0],
           [0, 0, 0, 0, 0, 0, 0, 0, 0]])
  
      # test default case
      result = clear_border(image.copy())
      ref = image.copy()
      ref[2, 0] = 0
      ref[0, -2] = 0
      assert_array_equal(result, ref)
  
      # test buffer
      result = clear_border(image.copy(), 1)
      assert_array_equal(result, np.zeros(result.shape))
  
      # test background value
      result = clear_border(image.copy(), buffer_size=1, bgval=2)
      assert_array_equal(result, 2 * np.ones_like(image))
  
  
  def test_clear_border_non_binary():
      image = np.array([[1, 2, 3, 1, 2],
                        [3, 4, 5, 4, 2],
                        [3, 4, 5, 4, 2],
                        [3, 3, 2, 1, 2]])
  
      result = clear_border(image.copy())
      expected = np.array([[0, 0, 0, 0, 0],
                           [0, 4, 5, 4, 0],
                           [0, 4, 5, 4, 0],
                           [0, 0, 0, 0, 0]])
  
      assert_array_equal(result, expected)
  
  
  if __name__ == "__main__":
      np.testing.run_module_suite()
  
new_contents: import numpy as np
  from numpy.testing import assert_array_equal
  from skimage.segmentation import clear_border
  
  
  def test_clear_border():
      image = np.array(
          [[0, 0, 0, 0, 0, 0, 0, 1, 0],
           [0, 0, 0, 0, 1, 0, 0, 0, 0],
           [1, 0, 0, 1, 0, 1, 0, 0, 0],
           [0, 0, 1, 1, 1, 1, 1, 0, 0],
           [0, 1, 1, 1, 1, 1, 1, 1, 0],
           [0, 0, 0, 0, 0, 0, 0, 0, 0]])
  
      # test default case
      result = clear_border(image.copy())
      ref = image.copy()
      ref[2, 0] = 0
      ref[0, -2] = 0
      assert_array_equal(result, ref)
  
      # test buffer
      result = clear_border(image.copy(), 1)
      assert_array_equal(result, np.zeros(result.shape))
  
      # test background value
      result = clear_border(image.copy(), buffer_size=1, bgval=2)
      assert_array_equal(result, 2 * np.ones_like(image))
  
  
  def test_clear_border_non_binary():
      image = np.array([[1, 2, 3, 1, 2],
                        [3, 3, 5, 4, 2],
                        [3, 4, 5, 4, 2],
                        [3, 3, 2, 1, 2]])
  
      result = clear_border(image.copy())
      expected = np.array([[0, 0, 0, 0, 0],
                           [0, 0, 5, 4, 0],
                           [0, 4, 5, 4, 0],
                           [0, 0, 0, 0, 0]])
  
      assert_array_equal(result, expected)
  
  
  if __name__ == "__main__":
      np.testing.run_module_suite()
  
subject: Improve test robustness