code: def test_all_to_all_estimated_output_blocks():
      # Test all to all operator
      input_op = InputDataBuffer(
          make_ref_bundles([[i] for i in range(100)])
      )
  
      def all_transform(bundles: List[RefBundle], ctx):
          return bundles, {}
  
      estimated_output_blocks = 500
      op1 = AllToAllOperator(
          all_transform,
          input_op,
          DataContext.get_current().target_max_block_size,
          estimated_output_blocks,
      )
      op2 = AllToAllOperator(
          all_transform,
          op1,
          DataContext.get_current().target_max_block_size,
      )
  
      while input_op.has_next():
          op1.add_input(input_op.get_next(), 0)
      op1.all_inputs_done()
      run_op_tasks_sync(op1)
  
      while op1.has_next():
          op2.add_input(op1.get_next(), 0)
      op2.all_inputs_done()
      run_op_tasks_sync(op2)
  
      # estimated output blocks for op2 should fallback to op1
      assert op2._estimated_output_blocks is None
      assert op2.num_outputs_total() == estimated_output_blocks
  
imports: import collections
  import random
  import time
  from typing import Any, Iterable, List
  from unittest.mock import MagicMock
  import numpy
  import pandas
  import pytest
  import ray
  from ray._private.test_utils import wait_for_condition
  from ray.data._internal.compute import ActorPoolStrategy, TaskPoolStrategy
  from ray.data._internal.execution.interfaces import ExecutionOptions, PhysicalOperator, RefBundle
  from ray.data._internal.execution.operators.actor_pool_map_operator import ActorPoolMapOperator
  from ray.data._internal.execution.operators.base_physical_operator import AllToAllOperator
  from ray.data._internal.execution.operators.input_data_buffer import InputDataBuffer
  from ray.data._internal.execution.operators.limit_operator import LimitOperator
  from ray.data._internal.execution.operators.map_operator import MapOperator, _BlockRefBundler
  from ray.data._internal.execution.operators.map_transformer import create_map_transformer_from_block_fn
  from ray.data._internal.execution.operators.output_splitter import OutputSplitter
  from ray.data._internal.execution.operators.task_pool_map_operator import TaskPoolMapOperator
  from ray.data._internal.execution.operators.union_operator import UnionOperator
  from ray.data._internal.execution.util import make_ref_bundles
  from ray.data.block import Block
  from ray.data.context import DataContext
  from ray.data.tests.util import run_one_op_task, run_op_tasks_sync
  from ray.tests.conftest import *
label_desc: Use image node_id 29 for calling a global function with example usage: test_all_to_all_estimated_output_blocks() and returns: bundles,  dict