text: """Common utilities for certbot_nginx."""
  import copy
  import os
  import pkg_resources
  import tempfile
  import unittest
  
  import mock
  import zope.component
  
  from acme import jose
  
  from certbot import configuration
  
  from certbot.tests import util as test_util
  
  from certbot.plugins import common
  
  from certbot_nginx import configurator
  from certbot_nginx import nginxparser
  
  
  class NginxTest(unittest.TestCase):  # pylint: disable=too-few-public-methods
  
      def setUp(self):
          super(NginxTest, self).setUp()
  
          self.temp_dir, self.config_dir, self.work_dir = common.dir_setup(
              "etc_nginx", "certbot_nginx.tests")
          self.logs_dir = tempfile.mkdtemp('logs')
  
          self.config_path = os.path.join(self.temp_dir, "etc_nginx")
  
          self.rsa512jwk = jose.JWKRSA.load(test_util.load_vector(
              "rsa512_key.pem"))
  
  
  def get_data_filename(filename):
      """Gets the filename of a test data file."""
      return pkg_resources.resource_filename(
          "certbot_nginx.tests", os.path.join(
              "testdata", "etc_nginx", filename))
  
  
  def get_nginx_configurator(
          config_path, config_dir, work_dir, logs_dir, version=(1, 6, 2)):
      """Create an Nginx Configurator with the specified options."""
  
      backups = os.path.join(work_dir, "backups")
  
      with mock.patch("certbot_nginx.configurator.NginxConfigurator."
                      "config_test"):
          with mock.patch("certbot_nginx.configurator.util."
                          "exe_exists") as mock_exe_exists:
              mock_exe_exists.return_value = True
              config = configurator.NginxConfigurator(
                  config=mock.MagicMock(
                      nginx_server_root=config_path,
                      le_vhost_ext="-le-ssl.conf",
                      config_dir=config_dir,
                      work_dir=work_dir,
                      logs_dir=logs_dir,
                      backup_dir=backups,
                      temp_checkpoint_dir=os.path.join(work_dir, "temp_checkpoints"),
                      in_progress_dir=os.path.join(backups, "IN_PROGRESS"),
                      server="https://acme-server.org:443/new",
                      tls_sni_01_port=5001,
                      dry_run=False,
                  ),
                  name="nginx",
                  version=version)
              config.prepare()
  
      # Provide general config utility.
      nsconfig = configuration.NamespaceConfig(config.config)
      zope.component.provideUtility(nsconfig)
  
      return config
  
  
  def filter_comments(tree):
      """Filter comment nodes from parsed configurations."""
  
      def traverse(tree):
          """Generator dropping comment nodes"""
          for entry in tree:
              # key, values = entry
              spaceless = [e for e in entry if not nginxparser.spacey(e)]
              if spaceless:
                  key = spaceless[0]
                  values = spaceless[1] if len(spaceless) > 1 else None
              else:
                  key = values = ""
              if isinstance(key, list):
                  new = copy.deepcopy(entry)
                  new[1] = filter_comments(values)
                  yield new
              else:
                  if key != '#' and spaceless:
                      yield spaceless
  
      return list(traverse(tree))
  
  
  def contains_at_depth(haystack, needle, n):
      """Is the needle in haystack at depth n?
  
      Return true if the needle is present in one of the sub-iterables in haystack
      at depth n. Haystack must be an iterable.
      """
      # Specifically use hasattr rather than isinstance(..., collections.Iterable)
      # because we want to include lists but reject strings.
      if not hasattr(haystack, '__iter__') or hasattr(haystack, 'strip'):
          return False
      if n == 0:
          return needle in haystack
      else:
          for item in haystack:
              if contains_at_depth(item, needle, n - 1):
                  return True
          return False
  