code: def test_diagonalize(self):
      hidden_states = self._get_hidden_states()
      hidden_states = hidden_states.reshape(
          (1, 8, 4)
      )  # set seq length = 8, hidden dim = 4
      chunked_hidden_states = LongformerSelfAttention._chunk(
          hidden_states, window_overlap=2
      )
      window_overlap_size = chunked_hidden_states.shape[2]
      self.assertTrue(window_overlap_size == 4)
  
      padded_hidden_states = (
          LongformerSelfAttention._pad_and_diagonalize(
              chunked_hidden_states
          )
      )
  
      self.assertTrue(
          padded_hidden_states.shape[-1]
          == chunked_hidden_states.shape[-1] + window_overlap_size - 1
      )
  
      # first row => [0.4983,  2.6918, -0.0071,  1.0492, 0.0000,  0.0000,  0.0000]
      self.assertTrue(
          torch.allclose(
              padded_hidden_states[0, 0, 0, :4],
              chunked_hidden_states[0, 0, 0],
              atol=1e-3,
          )
      )
      self.assertTrue(
          torch.allclose(
              padded_hidden_states[0, 0, 0, 4:],
              torch.zeros(
                  (3,), device=torch_device, dtype=torch.float32
              ),
              atol=1e-3,
          )
      )
      # last row => [0.0000,  0.0000,  0.0000, 2.0514, -1.1600,  0.5372,  0.2629]
      self.assertTrue(
          torch.allclose(
              padded_hidden_states[0, 0, -1, 3:],
              chunked_hidden_states[0, 0, -1],
              atol=1e-3,
          )
      )
      self.assertTrue(
          torch.allclose(
              padded_hidden_states[0, 0, -1, :3],
              torch.zeros(
                  (3,), device=torch_device, dtype=torch.float32
              ),
              atol=1e-3,
          )
      )
  
imports: import unittest
  from transformers import LongformerConfig, is_torch_available
  from transformers.testing_utils import require_sentencepiece, require_tokenizers, require_torch, slow, torch_device
  from ...test_configuration_common import ConfigTester
  from ...test_modeling_common import ModelTesterMixin, ids_tensor, random_attention_mask
label_desc: Use image node_id 2 for calling the LongformerModelIntegrationTest obj's underlying member method code with example usage: obj.test_diagonalize() without return types