code: def get_batch(self, source_l=3, bsize=1):
      # len x batch x nfeat
      test_src = torch.ones(bsize, source_l, 1).long()
      test_tgt = torch.ones(bsize, source_l, 1).long()
      test_length = torch.ones(bsize).fill_(source_l).long()
      return test_src, test_tgt, test_length
  
file_path: OpenNMT-py/onmt/tests/test_models.py
imports: import copy
  import unittest
  import torch
  import pyonmttok
  from onmt.constants import DefaultTokens
  from collections import Counter
  import onmt
  import onmt.inputters
  import onmt.opts
  from onmt.model_builder import build_embeddings, build_encoder, build_decoder
  from onmt.utils.parse import ArgumentParser
label_desc: Use image node_id 3 for calling the TestModel obj's underlying member method code with example usage: obj.get_batch(source_l, bsize) and returns: test_src,  test_tgt,  test_length