docstr: 测试fastnlp的dataset
  
  :return:
docstr_tok: ["\u6d4b\u8bd5fastnlp\u7684dataset",":","return",":"]
code: def test_fastnlp_Dataset(self):
      """
      测试fastnlp的dataset
  
      :return:
      """
      dataset = Fdataset(
          {"x": [[1, 2], [0], [2, 3, 4, 5]] * 100, "y": [0, 1, 2] * 100}
      )
      # jtl = JittorDataLoader(dataset, batch_size=16, drop_last=True)
      # jtl.set_pad("x", -1)
      # jtl.set_ignore("y")
      # for batch in jtl:
      #     assert batch['x'].size() == (16, 4)
      jtl1 = JittorDataLoader(
          dataset, batch_size=16, drop_last=True, num_workers=2
      )
      for batch in jtl1:
          print(batch)
  
file_path: fastNLP/tests/core/dataloaders/jittor_dataloader/test_fdl.py
imports: import pytest
  import numpy
  from fastNLP.envs import _module_available
  from fastNLP.core.dataloaders.jittor_dataloader import JittorDataLoader, prepare_jittor_dataloader
  from fastNLP.core.dataset import DataSet
  from fastNLP.core.collators import Collator
  from fastNLP.io.data_bundle import DataBundle
  from fastNLP.envs.imports import _NEED_IMPORT_JITTOR
label_desc: Use image node_id 2 for calling the TestJittor obj's underlying member method code with example usage: obj.test_fastnlp_Dataset() without return types