new_contents: import unittest
  
  import numpy as np
  
  from chainer import testing
  from chainercv.transforms import pca_lighting
  
  
  class TestPCALighting(unittest.TestCase):
  
      def test_pca_lighting(self):
          img = np.random.uniform(size=(3, 48, 32))
  
          out = pca_lighting(img, 0.1)
          self.assertEqual(img.shape, out.shape)
          self.assertEqual(img.dtype, out.dtype)
  
  
  testing.run_module(__name__, __file__)
  
subject: add test