code: def test_prepare(self):
      out = self.link._prepare(
          np.random.uniform(size=(self.in_channels, 286, 286))
      )
  
      self.assertEqual(out.shape, self.expected_shape)
  
imports: import numpy
  import unittest
  import chainer
  from chainer import testing
  from chainer.testing import attr
  from chainercv.links import FeaturePredictor
label_desc: Use image node_id 2 for calling the TestFeaturePredictor obj's underlying member method code with example usage: obj.test_prepare() without return types