import tensorflow as tf

      threads = [self.checkedThread(target=run_assign, args=(assign_op,))
                 for assign_op in assigns]
      for t in threads:
        t.start()
      for t in threads:
        t.join()

      vals = p.eval()

      # Assert every element is taken from one of the assignments.
      self.assertTrue((vals > 0).all())
      self.assertTrue((vals <= 20).all())


if __name__ == "__main__":
  tf.test.main()
