new_contents: import pytest
  import numpy as np
  
  from scipy import misc
  from gaps import image_helpers
  from gaps.size_detector import SizeDetector
  
  
  testdata = [
      28, 32, 48, 56, 64
  ]
  
  @pytest.mark.parametrize("size", testdata)
  def test_size_detection(size):
      puzzle = create_puzzle(size)
      detector = SizeDetector(puzzle)
      assert detector.detect_piece_size() == size
  
  def create_puzzle(piece_size):
      image = misc.imread("images/lena.jpg")
      pieces, rows, columns = image_helpers.flatten_image(image, piece_size)
      np.random.shuffle(pieces)
      return image_helpers.assemble_image(pieces, rows, columns)
  
subject: Test size detector