def test_trajectory_suffix_len(self):
    """Test that a trajectory suffix has the correct length."""
    tr = rl_task.Trajectory(observation=0)
    for _ in range(5):
      self._extend(tr)
    tr_suffix = tr.suffix(length=3)
    self.assertLen(tr_suffix, 3)
Test that a trajectory suffix has the correct length.
trax/rl/task_test.py