text: import cv2
  from plantcv.plantcv import stdev_filter
  
  
  def test_stdev_filter(test_data):
      """Test for PlantCV."""
      # Read in test data
      img = cv2.imread(test_data.small_gray_img, -1)
      filter_img = stdev_filter(img=img, ksize=11)
      assert img.shape == filter_img.shape
  