old_contents: import pytest
  import io
  import contextlib
  import tempfile
  import shutil
  import os
  
  from xd.docker.client import *
  
  
  DOCKER_HOST = os.environ.get('DOCKER_HOST', None)
  
  
  @pytest.fixture(scope="module")
  def docker(request):
      return DockerClient(host=DOCKER_HOST)
  
  
  class StreamRedirector(object):
  
      def __init__(self):
          self.stream = io.StringIO()
  
      def redirect(self):
          return contextlib.redirect_stdout(self.stream)
  
      def get(self):
          return self.stream.getvalue()
  
      def getlines(self):
          return self.stream.getvalue().rstrip('\n').split('\n')
  
      def lastline(self):
          lines = self.getlines()
          if not lines:
              return None
          return lines[-1]
  
  
  @pytest.fixture
  def stdout():
      return StreamRedirector()
  
  
  @pytest.fixture
  def cleandir(request):
      newdir = tempfile.mkdtemp()
      os.chdir(newdir)
      def remove_cleandir():
          shutil.rmtree(newdir)
      request.addfinalizer(remove_cleandir)
      return newdir
  
new_contents: import pytest
  import io
  import contextlib
  import tempfile
  import shutil
  import os
  
  from xd.docker.client import *
  
  
  DOCKER_HOST = os.environ.get('DOCKER_HOST', None)
  
  
  @pytest.fixture(scope="function")
  def docker(request):
      os.system("for c in `docker ps -a -q`;do docker rm $c;done")
      os.system("for i in `docker images -q`;do docker rmi $i;done")
      return DockerClient(host=DOCKER_HOST)
  
  
  class StreamRedirector(object):
  
      def __init__(self):
          self.stream = io.StringIO()
  
      def redirect(self):
          return contextlib.redirect_stdout(self.stream)
  
      def get(self):
          return self.stream.getvalue()
  
      def getlines(self):
          return self.stream.getvalue().rstrip('\n').split('\n')
  
      def lastline(self):
          lines = self.getlines()
          if not lines:
              return None
          return lines[-1]
  
  
  @pytest.fixture
  def stdout():
      return StreamRedirector()
  
  
  @pytest.fixture
  def cleandir(request):
      newdir = tempfile.mkdtemp()
      os.chdir(newdir)
      def remove_cleandir():
          shutil.rmtree(newdir)
      request.addfinalizer(remove_cleandir)
      return newdir
  
subject: Purge images and containers before each test