docstr: Test that the module is correctly wrapped in DDP
docstr_tok: ["Test","that","the","module","is","correctly","wrapped","in","DDP"]
code: def _test_prepare_module_ddp_strategy_wrapped_in_ddp() -> None:
      """
      Test that the module is correctly wrapped in DDP
      """
  
      ddp_module = prepare_module(
          module=torch.nn.Linear(2, 2),
          device=init_from_env(),
          strategy=DDPStrategy(),
      )
      tc = unittest.TestCase()
  
      tc.assertTrue(isinstance(ddp_module, DDP))
  
imports: import unittest
  from unittest.mock import patch
  import torch
  from torch.distributed.fsdp import FullyShardedDataParallel
  from torch.distributed.fsdp.fully_sharded_data_parallel import MixedPrecision
  from torch.nn.parallel import DistributedDataParallel
  from torchtnt.utils.env import init_from_env
  from torchtnt.utils.prepare_module import _is_fsdp_module, DDPStrategy, FSDPStrategy, NOOPStrategy, prepare_ddp, prepare_fsdp, prepare_module, TorchCompileParams
  from torchtnt.utils.test_utils import spawn_multi_process
  from torchtnt.utils.version import is_torch_version_geq_1_13, is_torch_version_geq_2_0
label_desc: Use image node_id 18 for calling the PrepareModelTest obj's underlying member method code with example usage: obj._test_prepare_module_ddp_strategy_wrapped_in_ddp() without return types