code: from dowel import logger
  import numpy as np
  
  from garage.sampler.utils import truncate_paths
  
  from tests.fixtures.logger import NullOutput
  
  
  class TestSampler:
  
      def setup_method(self):
          logger.add_output(NullOutput())
  
      def teardown_method(self):
          logger.remove_all()
  
      def test_truncate_paths(self):
          paths = [
              dict(
                  observations=np.zeros((100, 1)),
                  actions=np.zeros((100, 1)),
                  rewards=np.zeros(100),
                  env_infos=dict(),
                  agent_infos=dict(lala=np.zeros(100)),
              ),
              dict(
                  observations=np.zeros((50, 1)),
                  actions=np.zeros((50, 1)),
                  rewards=np.zeros(50),
                  env_infos=dict(),
                  agent_infos=dict(lala=np.zeros(50)),
              ),
          ]
  
          truncated = truncate_paths(paths, 130)
          assert len(truncated) == 2
          assert len(truncated[-1]['observations']) == 30
          assert len(truncated[0]['observations']) == 100
          # make sure not to change the original one
          assert len(paths) == 2
          assert len(paths[-1]['observations']) == 50
  
apis: numpy.zeros