docstr: 测试jittor类型的dataset使用fdl
  
  :return:
docstr_tok: ["\u6d4b\u8bd5jittor\u7c7b\u578b\u7684dataset\u4f7f\u7528fdl",":","return",":"]
code: def test_jittor_dataset(self):
      """
      测试jittor类型的dataset使用fdl
  
      :return:
      """
      dataset = MyDataset()
      jtl = JittorDataLoader(
          dataset, keep_numpy_array=False, batch_size=4
      )
      for batch in jtl:
          assert batch.size() == [4, 3, 4]
      jtl1 = JittorDataLoader(
          dataset, keep_numpy_array=False, batch_size=4, num_workers=2
      )
      for batch in jtl1:
          assert batch.size() == [4, 3, 4]
  
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 1 for calling the TestJittor obj's underlying member method code with example usage: obj.test_jittor_dataset() without return types