code: def test_identical_input(
      self, input_param, input_shape, target_shape
  ):
      with skip_if_downloading_fails():
          loss = PerceptualLoss(**input_param)
      tensor = torch.randn(input_shape)
      result = loss(tensor, tensor)
      self.assertEqual(result, torch.Tensor([0.0]))
  
file_path: MONAI/tests/test_perceptual_loss.py
imports: from __future__ import annotations
  import unittest
  import torch
  from parameterized import parameterized
  from monai.losses import PerceptualLoss
  from monai.utils import optional_import
  from tests.utils import SkipIfBeforePyTorchVersion, skip_if_downloading_fails, skip_if_quick
label_desc: Use image node_id 2 for calling the TestPerceptualLoss obj's underlying member method code with example usage: obj.test_identical_input(input_param, input_shape, target_shape) without return types