class_docstr: Abstract base class used to build new callbacks.
  
  Subclass this class and override any of the relevant hooks
class_docstr_tok: ["Abstract","base","class","used","to","build","new","callbacks",".","Subclass","this","class","and","override","any","of","the","relevant","hooks"]
docstr: Called when the test batch begins.
docstr_tok: ["Called","when","the","test","batch","begins","."]
code: def on_test_batch_start(
      self,
      trainer: "pl.Trainer",
      pl_module: "pl.LightningModule",
      batch: Any,
      batch_idx: int,
      dataloader_idx: int = 0,
  ) -> None:
      """Called when the test batch begins."""
  
imports: from typing import Any, Dict, Type
  from torch import Tensor
  from torch.optim import Optimizer
  import lightning.pytorch
  from lightning.pytorch.utilities.types import STEP_OUTPUT
label_desc: Use image node_id 22 for calling the Callback obj's underlying member method code with example usage: obj.on_test_batch_start(trainer, pl_module, batch, batch_idx, dataloader_idx) without return types