text: #!/usr/bin/env python
  
  """Test the copy of nose in this directory, by running that nose against itself.
  
  You can test nose using nose in other ways, but if you don't use this script,
  you might have one installation of nose testing another installation, which is
  not supported.
  """
  
  # More detail:
  
  # In the absence of some sort of deep renaming magic, nose can't reasonably
  # test a different installation of itself, given the existence of the global
  # module registry sys.modules .
  
  # If installed system-wide with setuptools, setuptools (via the site-packages
  # easy-install.pth) takes you at your word and ensures that the installed nose
  # comes first on sys.path .  So the only way to test a copy of nose other than
  # the installed one is to install that version (e.g. by running python setup.py
  # develop).
  
  # This script provides a way of running nose on nose's own tests without
  # installing the version to be tested, nor uninstalling the currently-installed
  # version.
  
  import glob
  import os
  import sys
  
  
  if __name__ == "__main__":
      this_dir = os.path.normpath(os.path.abspath(os.path.dirname(__file__)))
      lib_dirs = [this_dir]
      test_dir = this_dir
      if sys.version_info >= (3,):
          # Under Python 3.x, we need to 'build' the source (using 2to3, etc)
          # first.  'python3 setup.py build_tests' will put everything under
          # build/tests (including nose itself, since some tests are inside the
          # nose source)
          # The 'py3where' argument in setup.cfg will take care of making sure we
          # pull our tests only from the build/tests directory.  We just need to
          # make sure the right things are on sys.path.
          lib_dirs = glob.glob(os.path.join(this_dir, 'build', 'lib*'))
          test_dir = os.path.join(this_dir, 'build', 'tests')
          if not os.path.isdir(test_dir):
              raise AssertionError("Error: %s does not exist.  Use the setup.py 'build_tests' command to create it." % (test_dir,))
      try:
          import pkg_resources
          env = pkg_resources.Environment(search_path=lib_dirs)
          distributions = env["nose"]
          assert len(distributions) == 1, (
                  "Incorrect usage of selftest.py; please see DEVELOPERS.txt")
          dist = distributions[0]
          dist.activate()
      except ImportError:
          pass
      # Always make sure our chosen test dir is first on the path
      sys.path.insert(0, test_dir)
      import nose
      nose.run_exit()
  