def test_wanted_dirs(self):
        # _candidate_tempdir_list contains the expected directories

        # Make sure the interesting environment variables are all set.
        added = []
        try:
            for envname in 'TMPDIR', 'TEMP', 'TMP':
                dirname = os.getenv(envname)
                if not dirname:
                    os.environ[envname] = os.path.abspath(envname)
                    added.append(envname)

            cand = tempfile._candidate_tempdir_list()

            for envname in 'TMPDIR', 'TEMP', 'TMP':
                dirname = os.getenv(envname)
                if not dirname: raise ValueError
                self.assert_(dirname in cand)

            try:
                dirname = os.getcwd()
            except (AttributeError, os.error):
                dirname = os.curdir

            self.assert_(dirname in cand)

            # Not practical to try to verify the presence of OS-specific
            # paths in this list.
        finally:
            for p in added:
                del os.environ[p]

    def test_nonempty_list(self) -> None:
        # _candidate_tempdir_list returns a nonempty list of strings

        cand = tempfile._candidate_tempdir_list()

        self.assertFalse(len(cand) == 0)
        for c in cand:
            self.assertIsInstance(c, str)

    def test_nonempty_list(self):
        # _candidate_tempdir_list returns a nonempty list of strings

        cand = tempfile._candidate_tempdir_list()

        self.failIf(len(cand) == 0)
        for c in cand:
            self.assert_(isinstance(c, basestring), "%s is not a string" % c)

    def test_nonempty_list(self):
        # _candidate_tempdir_list returns a nonempty list of strings

        cand = tempfile._candidate_tempdir_list()

        self.assertFalse(len(cand) == 0)
        for c in cand:
            self.assertTrue(isinstance(c, str),
                         "%s is not a string" % c)

def find_good_temp_dir():
    """
    Given a list of candidate temp directories extracted from ``ansible.cfg``
    and stored in _candidate_temp_dirs, combine it with the Python-builtin list
    of candidate directories used by :mod:`tempfile`, then iteratively try each
    in turn until one is found that is both writeable and executable.
    """
    paths = [os.path.expandvars(os.path.expanduser(p))
             for p in _candidate_temp_dirs]
    paths.extend(tempfile._candidate_tempdir_list())

    for path in paths:
        try:
            tmp = tempfile.NamedTemporaryFile(
                prefix='ansible_mitogen_find_good_temp_dir',
                dir=path,
            )
        except (OSError, IOError) as e:
            LOG.debug('temp dir %r unusable: %s', path, e)
            continue

        try:
            try:
                os.chmod(tmp.name, int('0700', 8))
            except OSError as e:
                LOG.debug('temp dir %r unusable: %s: chmod failed: %s',
                          path, e)
                continue

            try:
                # access(.., X_OK) is sufficient to detect noexec.
                if not os.access(tmp.name, os.X_OK):
                    raise OSError('filesystem appears to be mounted noexec')
            except OSError as e:
                LOG.debug('temp dir %r unusable: %s: %s', path, e)
                continue

            LOG.debug('Selected temp directory: %r (from %r)', path, paths)
            return path
        finally:
            tmp.close()

    raise IOError(MAKE_TEMP_FAILED_MSG % {
        'paths': '\n    '.join(paths),
    })

    def test_wanted_dirs(self) -> None:
        # _candidate_tempdir_list contains the expected directories

        # Make sure the interesting environment variables are all set.
        with support.EnvironmentVarGuard() as env:
            for envname in 'TMPDIR', 'TEMP', 'TMP':
                dirname = os.getenv(envname)
                if not dirname:
                    env[envname] = os.path.abspath(envname)

            cand = tempfile._candidate_tempdir_list()

            for envname in 'TMPDIR', 'TEMP', 'TMP':
                dirname = os.getenv(envname)
                if not dirname: raise ValueError
                self.assertIn(dirname, cand)

            try:
                dirname = os.getcwd()
            except (AttributeError, os.error):
                dirname = os.curdir

            self.assertIn(dirname, cand)