grad_outputs->push_back(dx);
  grad_outputs->push_back(NoGradient());
  grad_outputs->push_back(NoGradient());
  return scope.status();
}
REGISTER_GRADIENT_OP("MaxPoolV2", MaxPoolGradV2Helper);

Status MaxPool3DGradHelper(const Scope& scope, const Operation& op,
                           const std::vector<Output>& grad_inputs,
                           std::vector<Output>* grad_outputs) {
  std::vector<int32> ksize;

  Tensor x_init_value = Tensor(DT_FLOAT, x_shape);
  SetRandomValuesForMaxPooling<float>(&x_init_value);
  RunTest(x, x_init_value, y, y_shape);
}

TEST_F(NNGradTest, MaxPool3DGradHelper) {
  TensorShape x_shape({1, 3, 3, 3, 1});
  TensorShape y_shape({1, 1, 1, 1, 1});
  auto x = Placeholder(scope_, DT_FLOAT, Placeholder::Shape(x_shape));
  // Setup window and strides so that we only do one MaxPool3D.