code: def test_zero(self):
      n_batch_axes = 0
      with pytest.raises(ValueError):
          functions.linear(self.x, self.W, n_batch_axes=n_batch_axes)
  
imports: import unittest
  import numpy
  import pytest
  import chainer
  from chainer import functions
  from chainer import testing
  from chainer.testing import backend
label_desc: Use image node_id 3 for calling the TestLinearNBatchAxesBoundaryCondition obj's underlying member method code with example usage: obj.test_zero() without return types