code: def test_configure_optimizer_from_dict(tmpdir):
      """Tests if `configure_optimizer` method could return a dictionary with `optimizer` field only."""
  
      class TestModel(BoringModel):
          def configure_optimizers(self):
              return {
                  "optimizer": optim.SGD(
                      params=self.parameters(), lr=1e-03
                  )
              }
  
      model = TestModel()
      trainer = Trainer(default_root_dir=tmpdir, fast_dev_run=True)
      trainer.fit(model)
  
imports: from unittest import mock
  from unittest.mock import call
  import pytest
  import torch
  from lightning.pytorch import Trainer
  from lightning.pytorch.callbacks import ModelCheckpoint
  from lightning.pytorch.core.optimizer import _configure_optimizers, _configure_schedulers_automatic_opt, _init_optimizers_and_lr_schedulers
  from lightning.pytorch.demos.boring_classes import BoringDataModule, BoringModel
  from lightning.pytorch.utilities.exceptions import MisconfigurationException
  from lightning.pytorch.utilities.types import LRSchedulerConfig
  from torch import optim
  from tests_pytorch.helpers.runif import RunIf
label_desc: Use image node_id 10 for calling a global function with example usage: test_configure_optimizer_from_dict(tmpdir) and returns: dict