path: root/Lib/test/test_tempfile.py

# tempfile.py unit tests.
import tempfile
import os
import signal
import sys
import re
import warnings

import unittest
from test import support


if hasattr(os, 'stat'):
    import stat
    has_stat = 1
else:
    has_stat = 0

has_textmode = (tempfile._text_openflags != tempfile._bin_openflags)
has_spawnl = hasattr(os, 'spawnl')

# TEST_FILES may need to be tweaked for systems depending on the maximum
# number of files that can be opened at one time (see ulimit -n)
if sys.platform.startswith('openbsd'):
    TEST_FILES = 48
else:
    TEST_FILES = 100

# This is organized as one test for each chunk of code in tempfile.py,
# in order of their appearance in the file.  Testing which requires
# threads is not done here.

# Common functionality.
class BaseTestCase(unittest.TestCase):

    str_check = re.compile(r"[a-zA-Z0-9_-]{6}$")

    def setUp(self):
        self._warnings_manager = support.check_warnings()
        self._warnings_manager.__enter__()
        warnings.filterwarnings("ignore", category=RuntimeWarning,
                                message="mktemp", module=__name__)

    def tearDown(self):
        self._warnings_manager.__exit__(None, None, None)


    def nameCheck(self, name, dir, pre, suf):
        (ndir, nbase) = os.path.split(name)
        npre  = nbase[:len(pre)]
        nsuf  = nbase[len(nbase)-len(suf):]

        # check for equality of the absolute paths!
        self.assertEqual(os.path.abspath(ndir), os.path.abspath(dir),
                         "file '%s' not in directory '%s'" % (name, dir))
        self.assertEqual(npre, pre,
                         "file '%s' does not begin with '%s'" % (nbase, pre))
        self.assertEqual(nsuf, suf,
                         "file '%s' does not end with '%s'" % (nbase, suf))

        nbase = nbase[len(pre):len(nbase)-len(suf)]
        self.assertTrue(self.str_check.match(nbase),
                     "random string '%s' does not match /^[a-zA-Z0-9_-]{6}$/"
                     % nbase)


class TestExports(BaseTestCase):
    def test_exports(self):
        # There are no surprising symbols in the tempfile module
        dict = tempfile.__dict__

        expected = {
            "NamedTemporaryFile" : 1,
            "TemporaryFile" : 1,
            "mkstemp" : 1,
            "mkdtemp" : 1,
            "mktemp" : 1,
            "TMP_MAX" : 1,
            "gettempprefix" : 1,
            "gettempdir" : 1,
            "tempdir" : 1,
            "template" : 1,
            "SpooledTemporaryFile" : 1,
            "TemporaryDirectory" : 1,
        }

        unexp = []
        for key in dict:
            if key[0] != '_' and key not in expected:
                unexp.append(key)
        self.assertTrue(len(unexp) == 0,
                        "unexpected keys: %s" % unexp)


class TestRandomNameSequence(BaseTestCase):
    """Test the internal iterator object _RandomNameSequence."""

    def setUp(self):
        self.r = tempfile._RandomNameSequence()
        super().setUp()

    def test_get_six_char_str(self):
        # _RandomNameSequence returns a six-character string
        s = next(self.r)
        self.nameCheck(s, '', '', '')

    def test_many(self):
        # _RandomNameSequence returns no duplicate strings (stochastic)

        dict = {}
        r = self.r
        for i in range(TEST_FILES):
            s = next(r)
            self.nameCheck(s, '', '', '')
            self.assertNotIn(s, dict)
            dict[s] = 1

    def supports_iter(self):
        # _RandomNameSequence supports the iterator protocol

        i = 0
        r = self.r
        for s in r:
            i += 1
            if i == 20:
                break

    @unittest.skipUnless(hasattr(os, 'fork'),
        "os.fork is required for this test")
    def test_process_awareness(self):
        # ensure that the random source differs between
        # child and parent.
        read_fd, write_fd = os.pipe()
        pid = None
        try:
            pid = os.fork()
            if not pid:
                os.close(read_fd)
                os.write(write_fd, next(self.r).encode("ascii"))
                os.close(write_fd)
                # bypass the normal exit handlers- leave those to
                # the parent.
                os._exit(0)
            parent_value = next(self.r)
            child_value = os.read(read_fd, len(parent_value)).decode("ascii")
        finally:
            if pid:
                # best effort to ensure the process can't bleed out
                # via any bugs above
                try:
                    os.kill(pid, signal.SIGKILL)
                except EnvironmentError:
                    pass
            os.close(read_fd)
            os.close(write_fd)
        self.assertNotEqual(child_value, parent_value)



class TestCandidateTempdirList(BaseTestCase):
    """Test the internal function _candidate_tempdir_list."""

    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.assertIsInstance(c, str)

    def test_wanted_dirs(self):
        # _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)

            # Not practical to try to verify the presence of OS-specific
            # paths in this list.


# We test _get_default_tempdir by testing gettempdir.


class TestGetCandidateNames(BaseTestCase):
    """Test the internal function _get_candidate_names."""

    def test_retval(self):
        # _get_candidate_names returns a _RandomNameSequence object
        obj = tempfile._get_candidate_names()
        self.assertIsInstance(obj, tempfile._RandomNameSequence)

    def test_same_thing(self):
        # _get_candidate_names always returns the same object
        a = tempfile._get_candidate_names()
        b = tempfile._get_candidate_names()

        self.assertTrue(a is b)


class TestMkstempInner(BaseTestCase):
    """Test the internal function _mkstemp_inner."""

    class mkstemped:
        _bflags = tempfile._bin_openflags
        _tflags = tempfile._text_openflags
        _close = os.close
        _unlink = os.unlink

        def __init__(self, dir, pre, suf, bin):
            if bin: flags = self._bflags
            else:   flags = self._tflags

            (self.fd, self.name) = tempfile._mkstemp_inner(dir, pre, suf, flags)

        def write(self, str):
            os.write(self.fd, str)

        def __del__(self):
            self._close(self.fd)
            self._unlink(self.name)

    def do_create(self, dir=None, pre="", suf="", bin=1):
        if dir is None:
            dir = tempfile.gettempdir()
        file = self.mkstemped(dir, pre, suf, bin)

        self.nameCheck(file.name, dir, pre, suf)
        return file

    def test_basic(self):
        # _mkstemp_inner can create files
        self.do_create().write(b"blat")
        self.do_create(pre="a").write(b"blat")
        self.do_create(suf="b").write(b"blat")
        self.do_create(pre="a", suf="b").write(b"blat")
        self.do_create(pre="aa", suf=".txt").write(b"blat")

    def test_basic_many(self):
        # _mkstemp_inner can create many files (stochastic)
        extant = list(range(TEST_FILES))
        for i in extant:
            extant[i] = self.do_create(pre="aa")

    def test_choose_directory(self):
        # _mkstemp_inner can create files in a user-selected directory
        dir = tempfile.mkdtemp()
        try:
            self.do_create(dir=dir).write(b"blat")
        finally:
            os.rmdir(dir)

    def test_file_mode(self):
        # _mkstemp_inner creates files with the proper mode
        if not has_stat:
            return            # ugh, can't use SkipTest.

        file = self.do_create()
        mode = stat.S_IMODE(os.stat(file.name).st_mode)
        expected = 0o600
        if sys.platform in ('win32', 'os2emx'):
            # There's no distinction among 'user', 'group' and 'world';
            # replicate the 'user' bits.
            user = expected >> 6
            expected = user * (1 + 8 + 64)
        self.assertEqual(mode, expected)

    def test_noinherit(self):
        # _mkstemp_inner file handles are not inherited by child processes
        if not has_spawnl:
            return            # ugh, can't use SkipTest.

        if support.verbose:
            v="v"
        else:
            v="q"

        file = self.do_create()
        fd = "%d" % file.fd

        try:
            me = __file__
        except NameError:
            me = sys.argv[0]

        # We have to exec something, so that FD_CLOEXEC will take
        # effect.  The core of this test is therefore in
        # tf_inherit_check.py, which see.
        tester = os.path.join(os.path.dirname(os.path.abspath(me)),
                              "tf_inherit_check.py")

        # On Windows a spawn* /path/ with embedded spaces shouldn't be quoted,
        # but an arg with embedded spaces should be decorated with double
        # quotes on each end
        if sys.platform in ('win32',):
            decorated = '"%s"' % sys.executable
            tester = '"%s"' % tester
        else:
            decorated = sys.executable

        retval = os.spawnl(os.P_WAIT, sys.executable, decorated, tester, v, fd)
        self.assertFalse(retval < 0,
                    "child process caught fatal signal %d" % -retval)
        self.assertFalse(retval > 0, "child process reports failure %d"%retval)

    def test_textmode(self):
        # _mkstemp_inner can create files in text mode
        if not has_textmode:
            return            # ugh, can't use SkipTest.

        # A text file is truncated at the first Ctrl+Z byte
        f = self.do_create(bin=0)
        f.write(b"blat\x1a")
        f.write(b"extra\n")
        os.lseek(f.fd, 0, os.SEEK_SET)
        self.assertEqual(os.read(f.fd, 20), b"blat")


class TestGetTempPrefix(BaseTestCase):
    """Test gettempprefix()."""

    def test_sane_template(self):
        # gettempprefix returns a nonempty prefix string
        p = tempfile.gettempprefix()

        self.assertIsInstance(p, str)
        self.assertTrue(len(p) > 0)

    def test_usable_template(self):
        # gettempprefix returns a usable prefix string

        # Create a temp directory, avoiding use of the prefix.
        # Then attempt to create a file whose name is
        # prefix + 'xxxxxx.xxx' in that directory.
        p = tempfile.gettempprefix() + "xxxxxx.xxx"
        d = tempfile.mkdtemp(prefix="")
        try:
            p = os.path.join(d, p)
            fd = os.open(p, os.O_RDWR | os.O_CREAT)
            os.close(fd)
            os.unlink(p)
        finally:
            os.rmdir(d)


class TestGetTempDir(BaseTestCase):
    """Test gettempdir()."""

    def test_directory_exists(self):
        # gettempdir returns a directory which exists

        dir = tempfile.gettempdir()
        self.assertTrue(os.path.isabs(dir) or dir == os.curdir,
                     "%s is not an absolute path" % dir)
        self.assertTrue(os.path.isdir(dir),
                     "%s is not a directory" % dir)

    def test_directory_writable(self):
        # gettempdir returns a directory writable by the user

        # sneaky: just instantiate a NamedTemporaryFile, which
        # defaults to writing into the directory returned by
        # gettempdir.
        file = tempfile.NamedTemporaryFile()
        file.write(b"blat")
        file.close()

    def test_same_thing(self):
        # gettempdir always returns the same object
        a = tempfile.gettempdir()
        b = tempfile.gettempdir()

        self.assertTrue(a is b)


class TestMkstemp(BaseTestCase):
    """Test mkstemp()."""

    def do_create(self, dir=None, pre="", suf=""):
        if dir is None:
            dir = tempfile.gettempdir()
        (fd, name) = tempfile.mkstemp(dir=dir, prefix=pre, suffix=suf)
        (ndir, nbase) = os.path.split(name)
        adir = os.path.abspath(dir)
        self.assertEqual(adir, ndir,
            "Directory '%s' incorrectly returned as '%s'" % (adir, ndir))

        try:
            self.nameCheck(name, dir, pre, suf)
        finally:
            os.close(fd)
            os.unlink(name)

    def test_basic(self):
        # mkstemp can create files
        self.do_create()
        self.do_create(pre="a")
        self.do_create(suf="b")
        self.do_create(pre="a", suf="b")
        self.do_create(pre="aa", suf=".txt")
        self.do_create(dir=".")

    def test_choose_directory(self):
        # mkstemp can create directories in a user-selected directory
        dir = tempfile.mkdtemp()
        try:
            self.do_create(dir=dir)
        finally:
            os.rmdir(dir)


class TestMkdtemp(BaseTestCase):
    """Test mkdtemp()."""

    def do_create(self, dir=None, pre="", suf=""):
        if dir is None:
            dir = tempfile.gettempdir()
        name = tempfile.mkdtemp(dir=dir, prefix=pre, suffix=suf)

        try:
            self.nameCheck(name, dir, pre, suf)
            return name
        except:
            os.rmdir(name)
            raise

    def test_basic(self):
        # mkdtemp can create directories
        os.rmdir(self.do_create())
        os.rmdir(self.do_create(pre="a"))
        os.rmdir(self.do_create(suf="b"))
        os.rmdir(self.do_create(pre="a", suf="b"))
        os.rmdir(self.do_create(pre="aa", suf=".txt"))

    def test_basic_many(self):
        # mkdtemp can create many directories (stochastic)
        extant = list(range(TEST_FILES))
        try:
            for i in extant:
                extant[i] = self.do_create(pre="aa")
        finally:
            for i in extant:
                if(isinstance(i, str)):
                    os.rmdir(i)

    def test_choose_directory(self):
        # mkdtemp can create directories in a user-selected directory
        dir = tempfile.mkdtemp()
        try:
            os.rmdir(self.do_create(dir=dir))
        finally:
            os.rmdir(dir)

    def test_mode(self):
        # mkdtemp creates directories with the proper mode
        if not has_stat:
            return            # ugh, can't use SkipTest.

        dir = self.do_create()
        try:
            mode = stat.S_IMODE(os.stat(dir).st_mode)
            mode &= 0o777 # Mask off sticky bits inherited from /tmp
            expected = 0o700
            if sys.platform in ('win32', 'os2emx'):
                # There's no distinction among 'user', 'group' and 'world';
                # replicate the 'user' bits.
                user = expected >> 6
                expected = user * (1 + 8 + 64)
            self.assertEqual(mode, expected)
        finally:
            os.rmdir(dir)


class TestMktemp(BaseTestCase):
    """Test mktemp()."""

    # For safety, all use of mktemp must occur in a private directory.
    # We must also suppress the RuntimeWarning it generates.
    def setUp(self):
        self.dir = tempfile.mkdtemp()
        super().setUp()

    def tearDown(self):
        if self.dir:
            os.rmdir(self.dir)
            self.dir = None
        super().tearDown()

    class mktemped:
        _unlink = os.unlink
        _bflags = tempfile._bin_openflags

        def __init__(self, dir, pre, suf):
            self.name = tempfile.mktemp(dir=dir, prefix=pre, suffix=suf)
            # Create the file.  This will raise an exception if it's
            # mysteriously appeared in the meanwhile.
            os.close(os.open(self.name, self._bflags, 0o600))

        def __del__(self):
            self._unlink(self.name)

    def do_create(self, pre="", suf=""):
        file = self.mktemped(self.dir, pre, suf)

        self.nameCheck(file.name, self.dir, pre, suf)
        return file

    def test_basic(self):
        # mktemp can choose usable file names
        self.do_create()
        self.do_create(pre="a")
        self.do_create(suf="b")
        self.do_create(pre="a", suf="b")
        self.do_create(pre="aa", suf=".txt")

    def test_many(self):
        # mktemp can choose many usable file names (stochastic)
        extant = list(range(TEST_FILES))
        for i in extant:
            extant[i] = self.do_create(pre="aa")

##     def test_warning(self):
##         # mktemp issues a warning when used
##         warnings.filterwarnings("error",
##                                 category=RuntimeWarning,
##                                 message="mktemp")
##         self.assertRaises(RuntimeWarning,
##                           tempfile.mktemp, dir=self.dir)


# We test _TemporaryFileWrapper by testing NamedTemporaryFile.


class TestNamedTemporaryFile(BaseTestCase):
    """Test NamedTemporaryFile()."""

    def do_create(self, dir=None, pre="", suf="", delete=True):
        if dir is None:
            dir = tempfile.gettempdir()
        file = tempfile.NamedTemporaryFile(dir=dir, prefix=pre, suffix=suf,
                                           delete=delete)

        self.nameCheck(file.name, dir, pre, suf)
        return file


    def test_basic(self):
        # NamedTemporaryFile can create files
        self.do_create()
        self.do_create(pre="a")
        self.do_create(suf="b")
        self.do_create(pre="a", suf="b")
        self.do_create(pre="aa", suf=".txt")

    def test_creates_named(self):
        # NamedTemporaryFile creates files with names
        f = tempfile.NamedTemporaryFile()
        self.assertTrue(os.path.exists(f.name),
                        "NamedTemporaryFile %s does not exist" % f.name)

    def test_del_on_close(self):
        # A NamedTemporaryFile is deleted when closed
        dir = tempfile.mkdtemp()
        try:
            f = tempfile.NamedTemporaryFile(dir=dir)
            f.write(b'blat')
            f.close()
            self.assertFalse(os.path.exists(f.name),
                        "NamedTemporaryFile %s exists after close" % f.name)
        finally:
            os.rmdir(dir)

    def test_dis_del_on_close(self):
        # Tests that delete-on-close can be disabled
        dir = tempfile.mkdtemp()
        tmp = None
        try:
            f = tempfile.NamedTemporaryFile(dir=dir, delete=False)
            tmp = f.name
            f.write(b'blat')
            f.close()
            self.assertTrue(os.path.exists(f.name),
                        "NamedTemporaryFile %s missing after close" % f.name)
        finally:
            if tmp is not None:
                os.unlink(tmp)
            os.rmdir(dir)

    def test_multiple_close(self):
        # A NamedTemporaryFile can be closed many times without error
        f = tempfile.NamedTemporaryFile()
        f.write(b'abc\n')
        f.close()
        f.close()
        f.close()

    def test_context_manager(self):
        # A NamedTemporaryFile can be used as a context manager
        with tempfile.NamedTemporaryFile() as f:
            self.assertTrue(os.path.exists(f.name))
        self.assertFalse(os.path.exists(f.name))
        def use_closed():
            with f:
                pass
        self.assertRaises(ValueError, use_closed)

    # How to test the mode and bufsize parameters?


class TestSpooledTemporaryFile(BaseTestCase):
    """Test SpooledTemporaryFile()."""

    def do_create(self, max_size=0, dir=None, pre="", suf=""):
        if dir is None:
            dir = tempfile.gettempdir()
        file = tempfile.SpooledTemporaryFile(max_size=max_size, dir=dir, prefix=pre, suffix=suf)

        return file


    def test_basic(self):
        # SpooledTemporaryFile can create files
        f = self.do_create()
        self.assertFalse(f._rolled)
        f = self.do_create(max_size=100, pre="a", suf=".txt")
        self.assertFalse(f._rolled)

    def test_del_on_close(self):
        # A SpooledTemporaryFile is deleted when closed
        dir = tempfile.mkdtemp()
        try:
            f = tempfile.SpooledTemporaryFile(max_size=10, dir=dir)
            self.assertFalse(f._rolled)
            f.write(b'blat ' * 5)
            self.assertTrue(f._rolled)
            filename = f.name
            f.close()
            self.assertFalse(isinstance(filename, str) and os.path.exists(filename),
                        "SpooledTemporaryFile %s exists after close" % filename)
        finally:
            os.rmdir(dir)

    def test_rewrite_small(self):
        # A SpooledTemporaryFile can be written to multiple within the max_size
        f = self.do_create(max_size=30)
        self.assertFalse(f._rolled)
        for i in range(5):
            f.seek(0, 0)
            f.write(b'x' * 20)
        self.assertFalse(f._rolled)

    def test_write_sequential(self):
        # A SpooledTemporaryFile should hold exactly max_size bytes, and roll
        # over afterward
        f = self.do_create(max_size=30)
        self.assertFalse(f._rolled)
        f.write(b'x' * 20)
        self.assertFalse(f._rolled)
        f.write(b'x' * 10)
        self.assertFalse(f._rolled)
        f.write(b'x')
        self.assertTrue(f._rolled)

    def test_writelines(self):
        # Verify writelines with a SpooledTemporaryFile
        f = self.do_create()
        f.writelines((b'x', b'y', b'z'))
        f.seek(0)
        buf = f.read()
        self.assertEqual(buf, b'xyz')

    def test_writelines_sequential(self):
        # A SpooledTemporaryFile should hold exactly max_size bytes, and roll
        # over afterward
        f = self.do_create(max_size=35)
        f.writelines((b'x' * 20, b'x' * 10, b'x' * 5))
        self.assertFalse(f._rolled)
        f.write(b'x')
        self.assertTrue(f._rolled)

    def test_sparse(self):
        # A SpooledTemporaryFile that is written late in the file will extend
        # when that occurs
        f = self.do_create(max_size=30)
        self.assertFalse(f._rolled)
        f.seek(100, 0)
        self.assertFalse(f._rolled)
        f.write(b'x')
        self.assertTrue(f._rolled)

    def test_fileno(self):
        # A SpooledTemporaryFile should roll over to a real file on fileno()
        f = self.do_create(max_size=30)
        self.assertFalse(f._rolled)
        self.assertTrue(f.fileno() > 0)
        self.assertTrue(f._rolled)

    def test_multiple_close_before_rollover(self):
        # A SpooledTemporaryFile can be closed many times without error
        f = tempfile.SpooledTemporaryFile()
        f.write(b'abc\n')
        self.assertFalse(f._rolled)
        f.close()
        f.close()
        f.close()

    def test_multiple_close_after_rollover(self):
        # A SpooledTemporaryFile can be closed many times without error
        f = tempfile.SpooledTemporaryFile(max_size=1)
        f.write(b'abc\n')
        self.assertTrue(f._rolled)
        f.close()
        f.close()
        f.close()

    def test_bound_methods(self):
        # It should be OK to steal a bound method from a SpooledTemporaryFile
        # and use it independently; when the file rolls over, those bound
        # methods should continue to function
        f = self.do_create(max_size=30)
        read = f.read
        write = f.write
        seek = f.seek

        write(b"a" * 35)
        write(b"b" * 35)
        seek(0, 0)
        self.assertEqual(read(70), b'a'*35 + b'b'*35)

    def test_text_mode(self):
        # Creating a SpooledTemporaryFile with a text mode should produce
        # a file object reading and writing (Unicode) text strings.
        f = tempfile.SpooledTemporaryFile(mode='w+', max_size=10)
        f.write("abc\n")
        f.seek(0)
        self.assertEqual(f.read(), "abc\n")
        f.write("def\n")
        f.seek(0)
        self.assertEqual(f.read(), "abc\ndef\n")
        f.write("xyzzy\n")
        f.seek(0)
        self.assertEqual(f.read(), "abc\ndef\nxyzzy\n")
        # Check that Ctrl+Z doesn't truncate the file
        f.write("foo\x1abar\n")
        f.seek(0)
        self.assertEqual(f.read(), "abc\ndef\nxyzzy\nfoo\x1abar\n")

    def test_text_newline_and_encoding(self):
        f = tempfile.SpooledTemporaryFile(mode='w+', max_size=10,
                                          newline='', encoding='utf-8')
        f.write("\u039B\r\n")
        f.seek(0)
        self.assertEqual(f.read(), "\u039B\r\n")
        self.assertFalse(f._rolled)

        f.write("\u039B" * 20 + "\r\n")
        f.seek(0)
        self.assertEqual(f.read(), "\u039B\r\n" + ("\u039B" * 20) + "\r\n")
        self.assertTrue(f._rolled)

    def test_context_manager_before_rollover(self):
        # A SpooledTemporaryFile can be used as a context manager
        with tempfile.SpooledTemporaryFile(max_size=1) as f:
            self.assertFalse(f._rolled)
            self.assertFalse(f.closed)
        self.assertTrue(f.closed)
        def use_closed():
            with f:
                pass
        self.assertRaises(ValueError, use_closed)

    def test_context_manager_during_rollover(self):
        # A SpooledTemporaryFile can be used as a context manager
        with tempfile.SpooledTemporaryFile(max_size=1) as f:
            self.assertFalse(f._rolled)
            f.write(b'abc\n')
            f.flush()
            self.assertTrue(f._rolled)
            self.assertFalse(f.closed)
        self.assertTrue(f.closed)
        def use_closed():
            with f:
                pass
        self.assertRaises(ValueError, use_closed)

    def test_context_manager_after_rollover(self):
        # A SpooledTemporaryFile can be used as a context manager
        f = tempfile.SpooledTemporaryFile(max_size=1)
        f.write(b'abc\n')
        f.flush()
        self.assertTrue(f._rolled)
        with f:
            self.assertFalse(f.closed)
        self.assertTrue(f.closed)
        def use_closed():
            with f:
                pass
        self.assertRaises(ValueError, use_closed)

    def test_truncate_with_size_parameter(self):
        # A SpooledTemporaryFile can be truncated to zero size
        f = tempfile.SpooledTemporaryFile(max_size=10)
        f.write(b'abcdefg\n')
        f.seek(0)
        f.truncate()
        self.assertFalse(f._rolled)
        self.assertEqual(f._file.getvalue(), b'')
        # A SpooledTemporaryFile can be truncated to a specific size
        f = tempfile.SpooledTemporaryFile(max_size=10)
        f.write(b'abcdefg\n')
        f.truncate(4)
        self.assertFalse(f._rolled)
        self.assertEqual(f._file.getvalue(), b'abcd')
        # A SpooledTemporaryFile rolls over if truncated to large size
        f = tempfile.SpooledTemporaryFile(max_size=10)
        f.write(b'abcdefg\n')
        f.truncate(20)
        self.assertTrue(f._rolled)
        if has_stat:
            self.assertEqual(os.fstat(f.fileno()).st_size, 20)


if tempfile.NamedTemporaryFile is not tempfile.TemporaryFile:

    class TestTemporaryFile(BaseTestCase):
        """Test TemporaryFile()."""

        def test_basic(self):
            # TemporaryFile can create files
            # No point in testing the name params - the file has no name.
            tempfile.TemporaryFile()

        def test_has_no_name(self):
            # TemporaryFile creates files with no names (on this system)
            dir = tempfile.mkdtemp()
            f = tempfile.TemporaryFile(dir=dir)
            f.write(b'blat')

            # Sneaky: because this file has no name, it should not prevent
            # us from removing the directory it was created in.
            try:
                os.rmdir(dir)
            except:
                # cleanup
                f.close()
                os.rmdir(dir)
                raise

        def test_multiple_close(self):
            # A TemporaryFile can be closed many times without error
            f = tempfile.TemporaryFile()
            f.write(b'abc\n')
            f.close()
            f.close()
            f.close()

        # How to test the mode and bufsize parameters?
        def test_mode_and_encoding(self):

            def roundtrip(input, *args, **kwargs):
                with tempfile.TemporaryFile(*args, **kwargs) as fileobj:
                    fileobj.write(input)
                    fileobj.seek(0)
                    self.assertEqual(input, fileobj.read())

            roundtrip(b"1234", "w+b")
            roundtrip("abdc\n", "w+")
            roundtrip("\u039B", "w+", encoding="utf-16")
            roundtrip("foo\r\n", "w+", newline="")


# Helper for test_del_on_shutdown
class NulledModules:
    def __init__(self, *modules):
        self.refs = [mod.__dict__ for mod in modules]
        self.contents = [ref.copy() for ref in self.refs]

    def __enter__(self):
        for d in self.refs:
            for key in d:
                d[key] = None

    def __exit__(self, *exc_info):
        for d, c in zip(self.refs, self.contents):
            d.clear()
            d.update(c)

class TestTemporaryDirectory(BaseTestCase):
    """Test TemporaryDirectory()."""

    def do_create(self, dir=None, pre="", suf="", recurse=1):
        if dir is None:
            dir = tempfile.gettempdir()
        tmp = tempfile.TemporaryDirectory(dir=dir, prefix=pre, suffix=suf)
        self.nameCheck(tmp.name, dir, pre, suf)
        # Create a subdirectory and some files
        if recurse:
            self.do_create(tmp.name, pre, suf, recurse-1)
        with open(os.path.join(tmp.name, "test.txt"), "wb") as f:
            f.write(b"Hello world!")
        return tmp

    def test_mkdtemp_failure(self):
        # Check no additional exception if mkdtemp fails
        # Previously would raise AttributeError instead
        # (noted as part of Issue #10188)
        with tempfile.TemporaryDirectory() as nonexistent:
            pass
        with self.assertRaises(os.error):
            tempfile.TemporaryDirectory(dir=nonexistent)

    def test_explicit_cleanup(self):
        # A TemporaryDirectory is deleted when cleaned up
        dir = tempfile.mkdtemp()
        try:
            d = self.do_create(dir=dir)
            self.assertTrue(os.path.exists(d.name),
                            "TemporaryDirectory %s does not exist" % d.name)
            d.cleanup()
            self.assertFalse(os.path.exists(d.name),
                        "TemporaryDirectory %s exists after cleanup" % d.name)
        finally:
            os.rmdir(dir)

    @support.skip_unless_symlink
    def test_cleanup_with_symlink_to_a_directory(self):
        # cleanup() should not follow symlinks to directories (issue #12464)
        d1 = self.do_create()
        d2 = self.do_create()

        # Symlink d1/foo -> d2
        os.symlink(d2.name, os.path.join(d1.name, "foo"))

        # This call to cleanup() should not follow the "foo" symlink
        d1.cleanup()

        self.assertFalse(os.path.exists(d1.name),
                         "TemporaryDirectory %s exists after cleanup" % d1.name)
        self.assertTrue(os.path.exists(d2.name),
                        "Directory pointed to by a symlink was deleted")
        self.assertEqual(os.listdir(d2.name), ['test.txt'],
                         "Contents of the directory pointed to by a symlink "
                         "were deleted")
        d2.cleanup()

    @support.cpython_only
    def test_del_on_collection(self):
        # A TemporaryDirectory is deleted when garbage collected
        dir = tempfile.mkdtemp()
        try:
            d = self.do_create(dir=dir)
            name = d.name
            del d # Rely on refcounting to invoke __del__
            self.assertFalse(os.path.exists(name),
                        "TemporaryDirectory %s exists after __del__" % name)
        finally:
            os.rmdir(dir)

    @unittest.expectedFailure # See issue #10188
    def test_del_on_shutdown(self):
        # A TemporaryDirectory may be cleaned up during shutdown
        # Make sure it works with the relevant modules nulled out
        with self.do_create() as dir:
            d = self.do_create(dir=dir)
            # Mimic the nulling out of modules that
            # occurs during system shutdown
            modules = [os, os.path]
            if has_stat:
                modules.append(stat)
            # Currently broken, so suppress the warning
            # that is otherwise emitted on stdout
            with support.captured_stderr() as err:
                with NulledModules(*modules):
                    d.cleanup()
            # Currently broken, so stop spurious exception by
            # indicating the object has already been closed
            d._closed = True
            # And this assert will fail, as expected by the
            # unittest decorator...
            self.assertFalse(os.path.exists(d.name),
                        "TemporaryDirectory %s exists after cleanup" % d.name)

    def test_warnings_on_cleanup(self):
        # Two kinds of warning on shutdown
        #   Issue 10888: may write to stderr if modules are nulled out
        #   ResourceWarning will be triggered by __del__
        with self.do_create() as dir:
            if os.sep != '\\':
                # Embed a backslash in order to make sure string escaping
                # in the displayed error message is dealt with correctly
                suffix = '\\check_backslash_handling'
            else:
                suffix = ''
            d = self.do_create(dir=dir, suf=suffix)

            #Check for the Issue 10888 message
            modules = [os, os.path]
            if has_stat:
                modules.append(stat)
            with support.captured_stderr() as err:
                with NulledModules(*modules):
                    d.cleanup()
            message = err.getvalue().replace('\\\\', '\\')
            self.assertIn("while cleaning up",  message)
            self.assertIn(d.name,  message)

            # Check for the resource warning
            with support.check_warnings(('Implicitly', ResourceWarning), quiet=False):
                warnings.filterwarnings("always", category=ResourceWarning)
                d.__del__()
            self.assertFalse(os.path.exists(d.name),
                        "TemporaryDirectory %s exists after __del__" % d.name)

    def test_multiple_close(self):
        # Can be cleaned-up many times without error
        d = self.do_create()
        d.cleanup()
        d.cleanup()
        d.cleanup()

    def test_context_manager(self):
        # Can be used as a context manager
        d = self.do_create()
        with d as name:
            self.assertTrue(os.path.exists(name))
            self.assertEqual(name, d.name)
        self.assertFalse(os.path.exists(name))


def test_main():
    support.run_unittest(__name__)

if __name__ == "__main__":
    test_main()