old_contents: import unittest
  
  from skimage import data, filters
  
  class TestSkImage(unittest.TestCase):
      def test_filter(self):
          image = data.coins()
          filters.sobel(image)
  
new_contents: import unittest
  
  from skimage import data, filters, io
  
  class TestSkImage(unittest.TestCase):
      def test_filter(self):
          image = data.coins()
          filters.sobel(image)
  
      def test_codecs(self):
          img = io.MultiImage('/input/tests/data/test.tif')
          
          self.assertEqual((10, 10, 4), img[0].shape)
subject: Add tif codec test.