code: def test(self):
      batch_size = self.batch_size
      m = self.m
      n_basis_functions = self.n_basis_functions
  
      x = np.random.uniform(size=(batch_size, m)).astype("f")
      y = iqn.cosine_basis_functions(
          x, n_basis_functions=n_basis_functions
      )
      self.assertEqual(y.shape, (batch_size, m, n_basis_functions))
  
      for i in range(batch_size):
          for j in range(m):
              for k in range(n_basis_functions):
                  self.assertAlmostEqual(
                      y[i, j, k],
                      np.cos(x[i, j] * (k + 1) * np.pi),
                      places=5,
                  )
  
imports: import unittest
  import numpy
  import chainer
  import chainer.functions
  import chainer.links
  from chainer import testing
  import basetest_dqn_like
  from basetest_training import _TestBatchTrainingMixin
  import chainerrl
  from chainerrl.agents import iqn
label_desc: Use image node_id 1 for calling the TestCosineBasisFunctions obj's underlying member method code with example usage: obj.test() without return types