new_contents: import pytest
  import cv2
  from plantcv.plantcv import flip
  
  
  def test_flip(test_data):
      # Read in test data
      img = cv2.imread(test_data.small_rgb_img)
      flipped_img = flip(img=img, direction="horizontal")
      assert img.shape == flipped_img.shape
  
  
  def test_flip_grayscale(test_data):
      # Read in test data
      gray_img = cv2.imread(test_data.small_gray_img, -1)
      flipped_img = flip(img=gray_img, direction="vertical")
      assert gray_img.shape == flipped_img.shape
  
  
  def test_flip_bad_input(test_data):
      img = cv2.imread(test_data.small_rgb_img)
      with pytest.raises(RuntimeError):
          _ = flip(img=img, direction="vert")
  
subject: Add flip tests module