code: def setUp(self):
      self.x = numpy.random.uniform(-1, 1, (2, 3)).astype(numpy.float32)
      self.t = numpy.random.randint(0, 2, (2,)).astype(numpy.int32)
      self.w = numpy.random.uniform(-1, 1, (5, 3)).astype(numpy.float32)
  
imports: import unittest
  import numpy
  import pytest
  import six
  import chainer
  from chainer.backend import CpuDevice
  from chainer.backends import cuda
  from chainer import functions
  from chainer.functions.loss import negative_sampling
  from chainer import gradient_check
  from chainer import testing
  from chainer.testing import attr
label_desc: Use image node_id 1 for calling the TestNegativeSamplingInvalidReductionOption obj's underlying member method code with example usage: obj.setUp() without return types