text: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from __future__ import unicode_literals
  
  import unittest
  
  from caffe2.python import workspace, core
  import caffe2.python.parallel_workers as parallel_workers
  
  
  def create_queue():
      queue = 'queue'
  
      workspace.RunOperatorOnce(
          core.CreateOperator(
              "CreateBlobsQueue", [], [queue], num_blobs=1, capacity=1000
          )
      )
  
      return queue
  
  
  def create_worker(queue, get_blob_data):
      def dummy_worker(worker_id):
          blob = 'blob_' + str(worker_id)
  
          workspace.FeedBlob(blob, get_blob_data(worker_id))
  
          workspace.RunOperatorOnce(
              core.CreateOperator(
                  'SafeEnqueueBlobs', [queue, blob], [blob, 'status_blob']
              )
          )
  
      return dummy_worker
  
  
  def dequeue_value(queue):
      dequeue_blob = 'dequeue_blob'
      workspace.RunOperatorOnce(
          core.CreateOperator(
              "SafeDequeueBlobs", [queue], [dequeue_blob, 'status_blob']
          )
      )
  
      return workspace.FetchBlob(dequeue_blob)
  
  
  class ParallelWorkersTest(unittest.TestCase):
      def testParallelWorkers(self):
          workspace.ResetWorkspace()
  
          queue = create_queue()
          dummy_worker = create_worker(queue, lambda worker_id: str(worker_id))
          worker_coordinator = parallel_workers.init_workers(dummy_worker)
          worker_coordinator.start()
  
          for _ in range(10):
              value = dequeue_value(queue)
              self.assertTrue(
                  value in [b'0', b'1'], 'Got unexpected value ' + str(value)
              )
  
          self.assertTrue(worker_coordinator.stop())
  
      def testParallelWorkersInitFun(self):
          workspace.ResetWorkspace()
  
          queue = create_queue()
          dummy_worker = create_worker(
              queue, lambda worker_id: workspace.FetchBlob('data')
          )
          workspace.FeedBlob('data', 'not initialized')
  
          def init_fun(worker_coordinator, global_coordinator):
              workspace.FeedBlob('data', 'initialized')
  
          worker_coordinator = parallel_workers.init_workers(
              dummy_worker, init_fun=init_fun
          )
          worker_coordinator.start()
  
          for _ in range(10):
              value = dequeue_value(queue)
              self.assertEqual(
                  value, b'initialized', 'Got unexpected value ' + str(value)
              )
  
          self.assertTrue(worker_coordinator.stop())
  
      def testParallelWorkersShutdownFun(self):
          workspace.ResetWorkspace()
  
          queue = create_queue()
          dummy_worker = create_worker(queue, lambda worker_id: str(worker_id))
          workspace.FeedBlob('data', 'not shutdown')
  
          def shutdown_fun():
              workspace.FeedBlob('data', 'shutdown')
  
          worker_coordinator = parallel_workers.init_workers(
              dummy_worker, shutdown_fun=shutdown_fun
          )
          worker_coordinator.start()
  
          self.assertTrue(worker_coordinator.stop())
  
          data = workspace.FetchBlob('data')
          self.assertEqual(data, b'shutdown', 'Got unexpected value ' + str(data))
  