code: def test_mask():
      args = make_arg()
      model, x, ilens, y, data, uttid_list = prepare(args)
  
      # check <sos>/<eos>, <mask> position
      n_char = len(args.char_list) + 1
      assert model.sos == n_char - 2
      assert model.eos == n_char - 2
      assert model.mask_token == n_char - 1
      yi, yo = mask_uniform(
          y, model.mask_token, model.eos, model.ignore_id
      )
      assert (
          (yi == model.mask_token).detach().numpy()
          == (yo != model.ignore_id).detach().numpy()
      ).all()
  
file_path: espnet/test/test_e2e_asr_maskctc.py
imports: import argparse
  import pytest
  import torch
  from espnet.nets.pytorch_backend.e2e_asr_maskctc import E2E
  from espnet.nets.pytorch_backend.maskctc.add_mask_token import mask_uniform
  from espnet.nets.pytorch_backend.transformer import plot
label_desc: Use image node_id 3 for calling a global function with example usage: test_mask() without return types