code: def test_mask_itemseq(self):
      config_dict = {
          "model": "BERT4Rec",
          "dataset": "seq_dataset",
          "data_path": current_path,
          "load_col": None,
          "train_neg_sample_args": None,
          "transform": "mask_itemseq",
          "mask_ratio": 1.0,
          "ft_ratio": 0.0,
      }
      train_dataset, valid_dataset, test_dataset = split_dataset(
          config_dict=config_dict
      )
      transform = new_transform(config_dict=config_dict)
  
      train_transform_interaction = transform(
          train_dataset, train_dataset.inter_feat
      )
      assert (
          train_transform_interaction[transform.MASK_ITEM_SEQ][
              :, :5
          ].numpy()
          == [
              [9, 0, 0, 0, 0],
              [9, 9, 0, 0, 0],
              [9, 9, 9, 0, 0],
              [9, 9, 9, 9, 0],
              [9, 9, 9, 9, 9],
              [9, 0, 0, 0, 0],
              [9, 0, 0, 0, 0],
              [9, 9, 0, 0, 0],
              [9, 0, 0, 0, 0],
          ]
      ).all()
  
      valid_transform_interaction = transform(
          valid_dataset, valid_dataset.inter_feat
      )
      assert (
          valid_transform_interaction[transform.MASK_ITEM_SEQ][
              :, :6
          ].numpy()
          == [[9, 9, 9, 9, 9, 9], [9, 9, 9, 0, 0, 0]]
      ).all()
  
      test_transform_interaction = transform(
          test_dataset, test_dataset.inter_feat
      )
      assert (
          test_transform_interaction[transform.MASK_ITEM_SEQ][
              :, :7
          ].numpy()
          == [
              [9, 9, 9, 9, 9, 9, 9],
              [9, 9, 9, 9, 0, 0, 0],
              [9, 9, 0, 0, 0, 0, 0],
          ]
      ).all()
  
file_path: RecBole/tests/data/test_transform.py
imports: import logging
  import os
  import math
  import numpy
  import pytest
  from recbole.config import Config
  from recbole.data import create_dataset
  from recbole.utils import init_seed
  from recbole.data.transform import construct_transform
label_desc: Use image node_id 1 for calling the TestTransform obj's underlying member method code with example usage: obj.test_mask_itemseq() without return types