code: def test_fit():
      trainer.model.fit = MagicMock()
      train_ds = MagicMock()
      trainer.fit(train_ds)
      trainer.model.fit.assert_called_once()
  
file_path: chitra/tests/test_trainer.py
imports: from unittest.mock import MagicMock
  import numpy
  import pytest
  import tensorflow
  from tensorflow import keras
  from chitra.trainer import Dataset, InterpretModel, Trainer, create_cnn
label_desc: Use image node_id 9 for calling a global function with example usage: test_fit() without return types