def test_ddp_sharded_plugin_finetune(tmpdir):
    """
        Test to ensure that we can save and restart training (simulate fine-tuning)
    """
    model = BoringModel()
    trainer = Trainer(
        gpus=2,
        accelerator='ddp_spawn',
        plugins=[DDPShardedPlugin()],
        fast_dev_run=True,
    )
    trainer.fit(model)

    checkpoint_path = os.path.join(tmpdir, 'model.pt')
    trainer.save_checkpoint(checkpoint_path)
    saved_model = BoringModel.load_from_checkpoint(checkpoint_path)

    trainer = Trainer(fast_dev_run=True, )
    trainer.fit(saved_model)
def test_ddp_sharded_plugin_checkpoint_cpu(tmpdir):
    """
        Test to ensure that checkpoint is saved correctly
    """
    model = BoringModel()
    trainer = Trainer(
        accelerator='ddp_cpu',
        plugins=[DDPShardedPlugin()],
        fast_dev_run=True,
    )

    trainer.fit(model)

    checkpoint_path = os.path.join(tmpdir, 'model.pt')
    trainer.save_checkpoint(checkpoint_path)
    saved_model = BoringModel.load_from_checkpoint(checkpoint_path)

    # Assert model parameters are identical after loading
    for ddp_param, shard_param in zip(model.parameters(),
                                      saved_model.parameters()):
        assert torch.equal(ddp_param, shard_param)