Python sys.base_prefix() Examples

def tearDown(self):
        if sys.version < "2.6" or hasattr(sys, 'real_prefix') or (hasattr(sys, 'base_prefix') and sys.base_prefix != sys.prefix):
            return

        os.chdir(self.old_cwd)
        shutil.rmtree(self.dir)
        shutil.rmtree(site.USER_BASE)
        shutil.rmtree(site.USER_SITE)
        site.USER_BASE = self.old_base
        site.USER_SITE = self.old_site 

def _find_config_dir(self, config_dir):
        # Look for config in the virtual environment
        # virtualenv puts the original prefix in sys.real_prefix
        # pyenv puts it in sys.base_prefix
        venv_d = os.path.join(sys.prefix, 'etc/a10')
        has_prefix = (hasattr(sys, 'real_prefix') or hasattr(sys, 'base_prefix'))

        env_override = os.environ.get('A10_CONFIG_DIR', None)
        if config_dir is not None:
            d = config_dir
        elif env_override is not None:
            d = env_override
        elif has_prefix and os.path.exists(venv_d):
            d = venv_d
        elif os.path.exists('/etc/neutron/services/loadbalancer/a10networks'):
            d = '/etc/neutron/services/loadbalancer/a10networks'
        else:
            d = '/etc/a10'

        return d 

def get_ns_wrapper(self):
        """
        Check if we're inside a virtualenv. If we are, then we should
        respect this and launch wrapper from venv as well.
        """
        if (hasattr(sys, 'real_prefix') or
            (hasattr(sys, 'base_prefix') and sys.base_prefix != sys.prefix)):
            ns_wrapper = os.path.join(sys.prefix, "bin/", self.NS_WRAPPER)
        else:
            ns_wrapper = self.NS_WRAPPER
        return ns_wrapper 

def test_user_similar(self):
        # Issue #8759: make sure the posix scheme for the users
        # is similar to the global posix_prefix one
        base = get_config_var('base')
        user = get_config_var('userbase')
        # the global scheme mirrors the distinction between prefix and
        # exec-prefix but not the user scheme, so we have to adapt the paths
        # before comparing (issue #9100)
        adapt = sys.base_prefix != sys.base_exec_prefix
        for name in ('stdlib', 'platstdlib', 'purelib', 'platlib'):
            global_path = get_path(name, 'posix_prefix')
            if adapt:
                global_path = global_path.replace(sys.exec_prefix, sys.base_prefix)
                base = base.replace(sys.exec_prefix, sys.base_prefix)
            elif sys.base_prefix != sys.prefix:
                # virtual environment? Likewise, we have to adapt the paths
                # before comparing
                global_path = global_path.replace(sys.base_prefix, sys.prefix)
                base = base.replace(sys.base_prefix, sys.prefix)
            user_path = get_path(name, 'posix_user')
            self.assertEqual(user_path, global_path.replace(base, user, 1)) 

def test_prefixes(self):
        """
        Test that the prefix values are as expected.
        """
        #check our prefixes
        self.assertEqual(sys.base_prefix, sys.prefix)
        self.assertEqual(sys.base_exec_prefix, sys.exec_prefix)

        # check a venv's prefixes
        rmtree(self.env_dir)
        self.run_with_capture(venv.create, self.env_dir)
        envpy = os.path.join(self.env_dir, self.bindir, self.exe)
        cmd = [envpy, '-c', None]
        for prefix, expected in (
            ('prefix', self.env_dir),
            ('prefix', self.env_dir),
            ('base_prefix', sys.prefix),
            ('base_exec_prefix', sys.exec_prefix)):
            cmd[2] = 'import sys; print(sys.%s)' % prefix
            p = subprocess.Popen(cmd, stdout=subprocess.PIPE,
                                 stderr=subprocess.PIPE)
            out, err = p.communicate()
            self.assertEqual(out.strip(), expected.encode()) 

def run(self, *args, **kwargs):
        func = kwargs.pop("func", Argv.get_output)
        kwargs.setdefault("stdin", DEVNULL)
        kwargs['env'] = deepcopy(os.environ)
        if 'VIRTUAL_ENV' in kwargs['env'] or 'CONDA_PREFIX' in kwargs['env']:
            kwargs['env'].pop('VIRTUAL_ENV', None)
            kwargs['env'].pop('CONDA_PREFIX', None)
            kwargs['env'].pop('PYTHONPATH', None)
            if hasattr(sys, "real_prefix") and hasattr(sys, "base_prefix"):
                path = ':'+kwargs['env']['PATH']
                path = path.replace(':'+sys.base_prefix, ':'+sys.real_prefix, 1)
                kwargs['env']['PATH'] = path

        if check_if_command_exists("poetry"):
            argv = Argv("poetry", *args)
        else:
            argv = Argv(self._python, "-m", "poetry", *args)
        self.log.debug("running: %s", argv)
        return func(argv, **kwargs) 

def test_prefixes(self):
        """
        Test that the prefix values are as expected.
        """
        #check our prefixes
        self.assertEqual(sys.base_prefix, sys.prefix)
        self.assertEqual(sys.base_exec_prefix, sys.exec_prefix)

        # check a venv's prefixes
        rmtree(self.env_dir)
        self.run_with_capture(venv.create, self.env_dir)
        envpy = os.path.join(self.env_dir, self.bindir, self.exe)
        cmd = [envpy, '-c', None]
        for prefix, expected in (
            ('prefix', self.env_dir),
            ('prefix', self.env_dir),
            ('base_prefix', sys.prefix),
            ('base_exec_prefix', sys.exec_prefix)):
            cmd[2] = 'import sys; print(sys.%s)' % prefix
            p = subprocess.Popen(cmd, stdout=subprocess.PIPE,
                                 stderr=subprocess.PIPE)
            out, err = p.communicate()
            self.assertEqual(out.strip(), expected.encode()) 

def inVirtualEnv():
    """
    Returns whether we are inside a virtualenv or Conda virtual environment.
    """
    return ('VIRTUAL_ENV' in os.environ or
            'CONDA_DEFAULT_ENV' in os.environ or
            hasattr(sys, 'real_prefix') or
            (hasattr(sys, 'base_prefix') and sys.base_prefix != sys.prefix)) 

def test_coverage(coverdir):
    trace = support.import_module('trace')
    tracer=trace.Trace(ignoredirs=[sys.base_prefix, sys.base_exec_prefix,],
                        trace=0, count=1)
    tracer.run('import importlib; importlib.reload(cmd); test_main()')
    r=tracer.results()
    print("Writing coverage results...")
    r.write_results(show_missing=True, summary=True, coverdir=coverdir) 

def change_prefix(filename, dst_prefix):
    prefixes = [sys.prefix]

    if is_darwin:
        prefixes.extend((
            os.path.join("/Library/Python", sys.version[:3], "site-packages"),
            os.path.join(sys.prefix, "Extras", "lib", "python"),
            os.path.join("~", "Library", "Python", sys.version[:3], "site-packages"),
            # Python 2.6 no-frameworks
            os.path.join("~", ".local", "lib","python", sys.version[:3], "site-packages"),
            # System Python 2.7 on OSX Mountain Lion
            os.path.join("~", "Library", "Python", sys.version[:3], "lib", "python", "site-packages")))

    if hasattr(sys, 'real_prefix'):
        prefixes.append(sys.real_prefix)
    if hasattr(sys, 'base_prefix'):
        prefixes.append(sys.base_prefix)
    prefixes = list(map(os.path.expanduser, prefixes))
    prefixes = list(map(os.path.abspath, prefixes))
    # Check longer prefixes first so we don't split in the middle of a filename
    prefixes = sorted(prefixes, key=len, reverse=True)
    filename = os.path.abspath(filename)
    for src_prefix in prefixes:
        if filename.startswith(src_prefix):
            _, relpath = filename.split(src_prefix, 1)
            if src_prefix != os.sep: # sys.prefix == "/"
                assert relpath[0] == os.sep
                relpath = relpath[1:]
            return join(dst_prefix, relpath)
    assert False, "Filename %s does not start with any of these prefixes: %s" % \
        (filename, prefixes) 

def test_coverage(coverdir):
    trace = support.import_module('trace')
    tracer=trace.Trace(ignoredirs=[sys.base_prefix, sys.base_exec_prefix,],
                        trace=0, count=1)
    tracer.run('import importlib; importlib.reload(cmd); test_main()')
    r=tracer.results()
    print("Writing coverage results...")
    r.write_results(show_missing=True, summary=True, coverdir=coverdir) 

def _running_under_venv():
    # type: () -> bool
    """Checks if sys.base_prefix and sys.prefix match.

    This handles PEP 405 compliant virtual environments.
    """
    return sys.prefix != getattr(sys, "base_prefix", sys.prefix) 

def version_cmd(options):
    from c7n.version import version
    from c7n.resources import load_available
    from c7n.mu import generate_requirements

    if not options.debug:
        print(version)
        return

    indent = 13

    print("\nPlease copy/paste the following info along with any bug reports:\n")
    print("Custodian:  ", version)
    pyversion = sys.version.replace('\n', '\n' + ' ' * indent)  # For readability
    print("Python:     ", pyversion)
    # os.uname is only available on recent versions of Unix
    try:
        print("Platform:   ", os.uname())
    except Exception:  # pragma: no cover
        print("Platform:  ", sys.platform)

    is_venv = (
        hasattr(sys, 'real_prefix') or
        (hasattr(sys, 'base_prefix') and sys.base_prefix != sys.prefix))
    print("Using venv: ", is_venv)
    in_container = os.path.exists('/.dockerenv')
    print("Docker: %s" % str(bool(in_container)))
    print("Installed: \n")

    packages = ['c7n']
    found = load_available(resources=False)
    if 'gcp' in found:
        packages.append('c7n_gcp')
    if 'azure' in found:
        packages.append('c7n_azure')
    if 'k8s' in found:
        packages.append('c7n_kube')
    print(generate_requirements(packages)) 

def setup_detect_python2():
        """
        Call this before using the refactoring tools to create them on demand
        if needed.
        """
        if None in [RTs._rt_py2_detect, RTs._rtp_py2_detect]:
            RTs._rt_py2_detect = RefactoringTool(py2_detect_fixers)
            RTs._rtp_py2_detect = RefactoringTool(py2_detect_fixers,
                                                  {'print_function': True})


# We need to find a prefix for the standard library, as we don't want to
# process any files there (they will already be Python 3).
#
# The following method is used by Sanjay Vinip in uprefix. This fails for
# ``conda`` environments:
#     # In a non-pythonv virtualenv, sys.real_prefix points to the installed Python.
#     # In a pythonv venv, sys.base_prefix points to the installed Python.
#     # Outside a virtual environment, sys.prefix points to the installed Python.

#     if hasattr(sys, 'real_prefix'):
#         _syslibprefix = sys.real_prefix
#     else:
#         _syslibprefix = getattr(sys, 'base_prefix', sys.prefix)

# Instead, we use the portion of the path common to both the stdlib modules
# ``math`` and ``urllib``. 

def _check_for_import_lib():
    """Check if an import library for the Python runtime already exists."""
    major_version, minor_version = tuple(sys.version_info[:2])

    # patterns for the file name of the library itself
    patterns = ['libpython%d%d.a',
                'libpython%d%d.dll.a',
                'libpython%d.%d.dll.a']

    # directory trees that may contain the library
    stems = [sys.prefix]
    if hasattr(sys, 'base_prefix') and sys.base_prefix != sys.prefix:
        stems.append(sys.base_prefix)
    elif hasattr(sys, 'real_prefix') and sys.real_prefix != sys.prefix:
        stems.append(sys.real_prefix)

    # possible subdirectories within those trees where it is placed
    sub_dirs = ['libs', 'lib']

    # generate a list of candidate locations
    candidates = []
    for pat in patterns:
        filename = pat % (major_version, minor_version)
        for stem_dir in stems:
            for folder in sub_dirs:
                candidates.append(os.path.join(stem_dir, folder, filename))

    # test the filesystem to see if we can find any of these
    for fullname in candidates:
        if os.path.isfile(fullname):
            # already exists, in location given
            return (True, fullname)

    # needs to be built, preferred location given first
    return (False, candidates[0]) 

def find_python_dll():
    # We can't do much here:
    # - find it in the virtualenv (sys.prefix)
    # - find it in python main dir (sys.base_prefix, if in a virtualenv)
    # - sys.real_prefix is main dir for virtualenvs in Python 2.7
    # - in system32,
    # - ortherwise (Sxs), I don't know how to get it.
    stems = [sys.prefix]
    if hasattr(sys, 'base_prefix') and sys.base_prefix != sys.prefix:
        stems.append(sys.base_prefix)
    elif hasattr(sys, 'real_prefix') and sys.real_prefix != sys.prefix:
        stems.append(sys.real_prefix)

    sub_dirs = ['', 'lib', 'bin']
    # generate possible combinations of directory trees and sub-directories
    lib_dirs = []
    for stem in stems:
        for folder in sub_dirs:
            lib_dirs.append(os.path.join(stem, folder))

    # add system directory as well
    if 'SYSTEMROOT' in os.environ:
        lib_dirs.append(os.path.join(os.environ['SYSTEMROOT'], 'System32'))

    # search in the file system for possible candidates
    major_version, minor_version = tuple(sys.version_info[:2])
    patterns = ['python%d%d.dll']

    for pat in patterns:
        dllname = pat % (major_version, minor_version)
        print("Looking for %s" % dllname)
        for folder in lib_dirs:
            dll = os.path.join(folder, dllname)
            if os.path.exists(dll):
                return dll

    raise ValueError("%s not found in %s" % (dllname, lib_dirs)) 

def is_virtual_env():
    if hasattr(sys, 'base_prefix'):
        # py3 case, with the stdlib venv
        return sys.base_prefix != sys.prefix
    return hasattr(sys, 'real_prefix')


# TODO: Really? Remove! 

def _check_for_import_lib():
    """Check if an import library for the Python runtime already exists."""
    major_version, minor_version = tuple(sys.version_info[:2])

    # patterns for the file name of the library itself
    patterns = ['libpython%d%d.a',
                'libpython%d%d.dll.a',
                'libpython%d.%d.dll.a']

    # directory trees that may contain the library
    stems = [sys.prefix]
    if hasattr(sys, 'base_prefix') and sys.base_prefix != sys.prefix:
        stems.append(sys.base_prefix)
    elif hasattr(sys, 'real_prefix') and sys.real_prefix != sys.prefix:
        stems.append(sys.real_prefix)

    # possible subdirectories within those trees where it is placed
    sub_dirs = ['libs', 'lib']

    # generate a list of candidate locations
    candidates = []
    for pat in patterns:
        filename = pat % (major_version, minor_version)
        for stem_dir in stems:
            for folder in sub_dirs:
                candidates.append(os.path.join(stem_dir, folder, filename))

    # test the filesystem to see if we can find any of these
    for fullname in candidates:
        if os.path.isfile(fullname):
            # already exists, in location given
            return (True, fullname)

    # needs to be built, preferred location given first
    return (False, candidates[0]) 

def find_python_dll():
    # We can't do much here:
    # - find it in the virtualenv (sys.prefix)
    # - find it in python main dir (sys.base_prefix, if in a virtualenv)
    # - sys.real_prefix is main dir for virtualenvs in Python 2.7
    # - in system32,
    # - ortherwise (Sxs), I don't know how to get it.
    stems = [sys.prefix]
    if hasattr(sys, 'base_prefix') and sys.base_prefix != sys.prefix:
        stems.append(sys.base_prefix)
    elif hasattr(sys, 'real_prefix') and sys.real_prefix != sys.prefix:
        stems.append(sys.real_prefix)

    sub_dirs = ['', 'lib', 'bin']
    # generate possible combinations of directory trees and sub-directories
    lib_dirs = []
    for stem in stems:
        for folder in sub_dirs:
            lib_dirs.append(os.path.join(stem, folder))

    # add system directory as well
    if 'SYSTEMROOT' in os.environ:
        lib_dirs.append(os.path.join(os.environ['SYSTEMROOT'], 'System32'))

    # search in the file system for possible candidates
    major_version, minor_version = tuple(sys.version_info[:2])
    patterns = ['python%d%d.dll']

    for pat in patterns:
        dllname = pat % (major_version, minor_version)
        print("Looking for %s" % dllname)
        for folder in lib_dirs:
            dll = os.path.join(folder, dllname)
            if os.path.exists(dll):
                return dll

    raise ValueError("%s not found in %s" % (dllname, lib_dirs)) 

def get_python_inc(plat_specific=0, prefix=None):
    """Return the directory containing installed Python header files.

    If 'plat_specific' is false (the default), this is the path to the
    non-platform-specific header files, i.e. Python.h and so on;
    otherwise, this is the path to platform-specific header files
    (namely pyconfig.h).

    If 'prefix' is supplied, use it instead of sys.base_prefix or
    sys.base_exec_prefix -- i.e., ignore 'plat_specific'.
    """
    if prefix is None:
        prefix = plat_specific and BASE_EXEC_PREFIX or BASE_PREFIX
    if os.name == "posix":
        if python_build:
            # Assume the executable is in the build directory.  The
            # pyconfig.h file should be in the same directory.  Since
            # the build directory may not be the source directory, we
            # must use "srcdir" from the makefile to find the "Include"
            # directory.
            if plat_specific:
                return _sys_home or project_base
            else:
                incdir = os.path.join(get_config_var('srcdir'), 'Include')
                return os.path.normpath(incdir)
        python_dir = 'python' + get_python_version() + build_flags
        return os.path.join(prefix, "include", python_dir)
    elif os.name == "nt":
        return os.path.join(prefix, "include")
    else:
        raise DistutilsPlatformError(
            "I don't know where Python installs its C header files "
            "on platform '%s'" % os.name) 

def test_coverage(coverdir):
    trace = support.import_module('trace')
    tracer = trace.Trace(ignoredirs=[sys.base_prefix, sys.base_exec_prefix,],
                         trace=0, count=1)
    tracer.run('test_main()')
    r = tracer.results()
    print('Writing coverage results...')
    r.write_results(show_missing=True, summary=True,
                    coverdir=coverdir) 

def test_coverage_ignore(self):
        # Ignore all files, nothing should be traced nor printed
        libpath = os.path.normpath(os.path.dirname(os.__file__))
        # sys.prefix does not work when running from a checkout
        tracer = trace.Trace(ignoredirs=[sys.base_prefix, sys.base_exec_prefix,
                             libpath], trace=0, count=1)
        with captured_stdout() as stdout:
            self._coverage(tracer)
        if os.path.exists(TESTFN):
            files = os.listdir(TESTFN)
            self.assertEqual(files, ['_importlib.cover'])  # Ignore __import__ 

def get_python_lib(plat_specific=0, standard_lib=0, prefix=None):
    """Return the directory containing the Python library (standard or
    site additions).

    If 'plat_specific' is true, return the directory containing
    platform-specific modules, i.e. any module from a non-pure-Python
    module distribution; otherwise, return the platform-shared library
    directory.  If 'standard_lib' is true, return the directory
    containing standard Python library modules; otherwise, return the
    directory for site-specific modules.

    If 'prefix' is supplied, use it instead of sys.base_prefix or
    sys.base_exec_prefix -- i.e., ignore 'plat_specific'.
    """
    if prefix is None:
        if standard_lib:
            prefix = plat_specific and BASE_EXEC_PREFIX or BASE_PREFIX
        else:
            prefix = plat_specific and EXEC_PREFIX or PREFIX

    if os.name == "posix":
        libpython = os.path.join(prefix,
                                 "lib", "python" + get_python_version())
        if standard_lib:
            return libpython
        else:
            return os.path.join(libpython, "site-packages")
    elif os.name == "nt":
        if standard_lib:
            return os.path.join(prefix, "Lib")
        else:
            return os.path.join(prefix, "Lib", "site-packages")
    else:
        raise DistutilsPlatformError(
            "I don't know where Python installs its library "
            "on platform '%s'" % os.name) 

def get_python_inc(plat_specific=0, prefix=None):
    """Return the directory containing installed Python header files.

    If 'plat_specific' is false (the default), this is the path to the
    non-platform-specific header files, i.e. Python.h and so on;
    otherwise, this is the path to platform-specific header files
    (namely pyconfig.h).

    If 'prefix' is supplied, use it instead of sys.base_prefix or
    sys.base_exec_prefix -- i.e., ignore 'plat_specific'.
    """
    if prefix is None:
        prefix = plat_specific and BASE_EXEC_PREFIX or BASE_PREFIX
    if os.name == "posix":
        if python_build:
            # Assume the executable is in the build directory.  The
            # pyconfig.h file should be in the same directory.  Since
            # the build directory may not be the source directory, we
            # must use "srcdir" from the makefile to find the "Include"
            # directory.
            base = _sys_home or project_base
            if plat_specific:
                return base
            if _sys_home:
                incdir = os.path.join(_sys_home, get_config_var('AST_H_DIR'))
            else:
                incdir = os.path.join(get_config_var('srcdir'), 'Include')
            return os.path.normpath(incdir)
        python_dir = 'python' + get_python_version() + build_flags
        return os.path.join(prefix, "include", python_dir)
    elif os.name == "nt":
        return os.path.join(prefix, "include")
    else:
        raise DistutilsPlatformError(
            "I don't know where Python installs its C header files "
            "on platform '%s'" % os.name) 

def get_python_lib(plat_specific=0, standard_lib=0, prefix=None):
    """Return the directory containing the Python library (standard or
    site additions).

    If 'plat_specific' is true, return the directory containing
    platform-specific modules, i.e. any module from a non-pure-Python
    module distribution; otherwise, return the platform-shared library
    directory.  If 'standard_lib' is true, return the directory
    containing standard Python library modules; otherwise, return the
    directory for site-specific modules.

    If 'prefix' is supplied, use it instead of sys.base_prefix or
    sys.base_exec_prefix -- i.e., ignore 'plat_specific'.
    """
    if prefix is None:
        if standard_lib:
            prefix = plat_specific and BASE_EXEC_PREFIX or BASE_PREFIX
        else:
            prefix = plat_specific and EXEC_PREFIX or PREFIX

    if os.name == "posix":
        libpython = os.path.join(prefix,
                                 "lib", "python" + get_python_version())
        if standard_lib:
            return libpython
        else:
            return os.path.join(libpython, "site-packages")
    elif os.name == "nt":
        if standard_lib:
            return os.path.join(prefix, "Lib")
        else:
            if get_python_version() < "2.2":
                return prefix
            else:
                return os.path.join(prefix, "Lib", "site-packages")
    else:
        raise DistutilsPlatformError(
            "I don't know where Python installs its library "
            "on platform '%s'" % os.name) 

def get_python_inc(plat_specific=0, prefix=None):
    """Return the directory containing installed Python header files.

    If 'plat_specific' is false (the default), this is the path to the
    non-platform-specific header files, i.e. Python.h and so on;
    otherwise, this is the path to platform-specific header files
    (namely pyconfig.h).

    If 'prefix' is supplied, use it instead of sys.base_prefix or
    sys.base_exec_prefix -- i.e., ignore 'plat_specific'.
    """
    if prefix is None:
        prefix = plat_specific and BASE_EXEC_PREFIX or BASE_PREFIX
    if os.name == "posix":
        if python_build:
            # Assume the executable is in the build directory.  The
            # pyconfig.h file should be in the same directory.  Since
            # the build directory may not be the source directory, we
            # must use "srcdir" from the makefile to find the "Include"
            # directory.
            base = _sys_home or project_base
            if plat_specific:
                return base
            if _sys_home:
                incdir = os.path.join(_sys_home, get_config_var('AST_H_DIR'))
            else:
                incdir = os.path.join(get_config_var('srcdir'), 'Include')
            return os.path.normpath(incdir)
        python_dir = 'python' + get_python_version() + build_flags
        return os.path.join(prefix, "include", python_dir)
    elif os.name == "nt":
        return os.path.join(prefix, "include")
    else:
        raise DistutilsPlatformError(
            "I don't know where Python installs its C header files "
            "on platform '%s'" % os.name) 

def _check_for_import_lib():
    """Check if an import library for the Python runtime already exists."""
    major_version, minor_version = tuple(sys.version_info[:2])

    # patterns for the file name of the library itself
    patterns = ['libpython%d%d.a',
                'libpython%d%d.dll.a',
                'libpython%d.%d.dll.a']

    # directory trees that may contain the library
    stems = [sys.prefix]
    if hasattr(sys, 'base_prefix') and sys.base_prefix != sys.prefix:
        stems.append(sys.base_prefix)
    elif hasattr(sys, 'real_prefix') and sys.real_prefix != sys.prefix:
        stems.append(sys.real_prefix)

    # possible subdirectories within those trees where it is placed
    sub_dirs = ['libs', 'lib']

    # generate a list of candidate locations
    candidates = []
    for pat in patterns:
        filename = pat % (major_version, minor_version)
        for stem_dir in stems:
            for folder in sub_dirs:
                candidates.append(os.path.join(stem_dir, folder, filename))

    # test the filesystem to see if we can find any of these
    for fullname in candidates:
        if os.path.isfile(fullname):
            # already exists, in location given
            return (True, fullname)

    # needs to be built, preferred location given first
    return (False, candidates[0]) 

def find_python_dll():
    # We can't do much here:
    # - find it in the virtualenv (sys.prefix)
    # - find it in python main dir (sys.base_prefix, if in a virtualenv)
    # - sys.real_prefix is main dir for virtualenvs in Python 2.7
    # - in system32,
    # - ortherwise (Sxs), I don't know how to get it.
    stems = [sys.prefix]
    if hasattr(sys, 'base_prefix') and sys.base_prefix != sys.prefix:
        stems.append(sys.base_prefix)
    elif hasattr(sys, 'real_prefix') and sys.real_prefix != sys.prefix:
        stems.append(sys.real_prefix)

    sub_dirs = ['', 'lib', 'bin']
    # generate possible combinations of directory trees and sub-directories
    lib_dirs = []
    for stem in stems:
        for folder in sub_dirs:
            lib_dirs.append(os.path.join(stem, folder))

    # add system directory as well
    if 'SYSTEMROOT' in os.environ:
        lib_dirs.append(os.path.join(os.environ['SYSTEMROOT'], 'System32'))

    # search in the file system for possible candidates
    major_version, minor_version = tuple(sys.version_info[:2])
    patterns = ['python%d%d.dll']

    for pat in patterns:
        dllname = pat % (major_version, minor_version)
        print("Looking for %s" % dllname)
        for folder in lib_dirs:
            dll = os.path.join(folder, dllname)
            if os.path.exists(dll):
                return dll

    raise ValueError("%s not found in %s" % (dllname, lib_dirs)) 

def setUp(self):
            base = sys.base_prefix
            self.dir = get_python_lib(
                standard_lib=True, plat_specific=True, prefix=base
            )
            super(TestBasePlatLibDir, self).setUp() 

def setUp(self):
            base = sys.base_prefix
            self.dir = get_python_lib(
                standard_lib=True, plat_specific=False, prefix=base
            )
            super(TestBasePureLibDir, self).setUp()