new_contents: import numpy as np
  import unittest
  
  import chainer
  from chainer import testing
  from chainer.testing import attr
  
  from chainercv.links import SSD300
  from chainercv.links import SSD512
  
  
  @testing.parameterize(*testing.product({
      'insize': [300, 512],
      'n_class': [1, 5, 20],
  }))
  class TestSSD(unittest.TestCase):
  
      def setUp(self):
          if self.insize == 300:
              self.link = SSD300(n_class=self.n_class)
              self.n_bbox = 8732
          elif self.insize == 512:
              self.link = SSD512(n_class=self.n_class)
              self.n_bbox = 24564
  
      def _random_array(self, shape):
          return self.link.xp.array(
              np.random.uniform(-1, 1, size=shape), dtype=np.float32)
  
      def _random_image(self, width, height):
          return np.random.randint(0, 255, size=(3, height, width))
  
      def _check_call(self):
          x = self._random_array((1, 3, self.insize, self.insize))
  
          loc, conf = self.link(x)
  
          self.assertIsInstance(loc, chainer.Variable)
          self.assertIsInstance(loc.data, self.link.xp.ndarray)
          self.assertEqual(loc.shape, (1, self.n_bbox, 4))
          self.assertIsInstance(conf, chainer.Variable)
          self.assertIsInstance(conf.data, self.link.xp.ndarray)
          self.assertEqual(conf.shape, (1, self.n_bbox, self.n_class + 1))
  
      @attr.slow
      def test_call_cpu(self):
          self._check_call()
  
      @attr.gpu
      @attr.slow
      def test_call_gpu(self):
          self.link.to_gpu()
          self._check_call()
  
      def test_prepare(self):
          img = self._random_image(640, 480)
          img = self.link.prepare(img)
          self.assertEqual(img.shape, (3, self.insize, self.insize))
  
  
  testing.run_module(__name__, __file__)
  
subject: add tests for SSD300 and SSD512