new_contents: import cv2
  import numpy as np
  from plantcv.plantcv import distance_transform
  
  
  def test_distance_transform(test_data):
      # Read in test data
      mask = cv2.imread(test_data.small_bin_img, -1)
      distance_transform_img = distance_transform(bin_img=mask, distance_type=1, mask_size=3)
      # Assert that the output image has the dimensions of the input image and is binary
      assert mask.shape == distance_transform_img.shape and distance_transform_img.dtype == np.float32
  
subject: Add distance_transform tests module