docstr: Test predict entry point with a callback
docstr_tok: ["Test","predict","entry","point","with","a","callback"]
code: def test_predict_with_callback(self) -> None:
      """
      Test predict entry point with a callback
      """
      input_dim = 2
      dataset_len = 10
      batch_size = 2
      max_steps_per_epoch = 6
      expected_num_steps = dataset_len / batch_size
  
      my_unit = DummyPredictUnit(2)
      dataloader = generate_random_dataloader(
          dataset_len, input_dim, batch_size
      )
      callback_mock = MagicMock()
      predict(
          my_unit,
          dataloader,
          max_steps_per_epoch=max_steps_per_epoch,
          callbacks=[callback_mock],
      )
  
      self.assertEqual(callback_mock.on_predict_start.call_count, 1)
      self.assertEqual(
          callback_mock.on_predict_epoch_start.call_count, 1
      )
      self.assertEqual(
          callback_mock.on_predict_step_start.call_count,
          expected_num_steps,
      )
      self.assertEqual(
          callback_mock.on_predict_step_end.call_count,
          expected_num_steps,
      )
      self.assertEqual(callback_mock.on_predict_epoch_end.call_count, 1)
      self.assertEqual(callback_mock.on_predict_end.call_count, 1)
  
imports: import unittest
  from typing import Any, Iterator, Mapping, Tuple
  from unittest.mock import MagicMock
  import torch
  from torch import nn
  from torchtnt.framework._test_utils import DummyPredictUnit, generate_random_dataloader
  from torchtnt.framework.callback import Callback
  from torchtnt.framework.predict import predict
  from torchtnt.framework.state import State
  from torchtnt.framework.unit import PredictUnit, TPredictUnit
  from torchtnt.utils.timer import Timer
label_desc: Use image node_id 4 for calling the PredictTest obj's underlying member method code with example usage: obj.test_predict_with_callback() without return types