code: def test_gray2yuv():
      cv_gray = cv.imread(tens_path)
      cv_gray = cv.cvtColor(cv_gray, cv.COLOR_BGR2GRAY)
      yuv = caer.gray2yuv(cv_gray)
  
      assert len(yuv.shape) == 3
      assert isinstance(yuv, caer.Tensor)
      assert yuv.is_yuv()
  
file_path: caer/tests/color/test_gray.py
imports: import caer
  import cv2
  import os
label_desc: Use image node_id 6 for calling a global function with example usage: test_gray2yuv() without return types