new_contents: import cv2
  from plantcv.plantcv import sobel_filter
  
  
  def test_sobel_filter(test_data):
      # Read in test data
      img = cv2.imread(test_data.small_gray_img, -1)
      sobel_img = sobel_filter(gray_img=img, dx=1, dy=0, ksize=1)
      # Assert that the output image has the dimensions of the input image
      assert img.shape == sobel_img.shape
  
subject: Create sobel_filter tests module