view tests/test-atomictempfile.py @ 29489:54ad81b0665f

sslutil: handle default CA certificate loading on Windows

See the inline comment for what's going on here.

There is magic built into the "ssl" module that ships with modern
CPython that knows how to load the system CA certificates on
Windows. Since we're not shipping a CA bundle with Mercurial,
if we're running on legacy CPython there's nothing we can do
to load CAs on Windows, so it makes sense to print a warning.

I don't anticipate many people will see this warning because
the official (presumed popular) Mercurial distributions on
Windows bundle Python and should be distributing a modern Python
capable of loading system CA certs.

from __future__ import absolute_import

import glob
import os
import shutil
import tempfile
import unittest

from mercurial import (
    util,
)
atomictempfile = util.atomictempfile

class testatomictempfile(unittest.TestCase):
    def setUp(self):
        self._testdir = tempfile.mkdtemp('atomictempfiletest')
        self._filename = os.path.join(self._testdir, 'testfilename')

    def tearDown(self):
        shutil.rmtree(self._testdir, True)

    def testsimple(self):
        file = atomictempfile(self._filename)
        self.assertFalse(os.path.isfile(self._filename))
        tempfilename = file._tempname
        self.assertTrue(tempfilename in glob.glob(
            os.path.join(self._testdir, '.testfilename-*')))

        file.write(b'argh\n')
        file.close()

        self.assertTrue(os.path.isfile(self._filename))
        self.assertTrue(tempfilename not in glob.glob(
            os.path.join(self._testdir, '.testfilename-*')))

    # discard() removes the temp file without making the write permanent
    def testdiscard(self):
        file = atomictempfile(self._filename)
        (dir, basename) = os.path.split(file._tempname)

        file.write(b'yo\n')
        file.discard()

        self.assertFalse(os.path.isfile(self._filename))
        self.assertTrue(basename not in os.listdir('.'))

    # if a programmer screws up and passes bad args to atomictempfile, they
    # get a plain ordinary TypeError, not infinite recursion
    def testoops(self):
        self.assertRaises(TypeError, atomictempfile)

    # checkambig=True avoids ambiguity of timestamp
    def testcheckambig(self):
        def atomicwrite(checkambig):
            f = atomictempfile(self._filename, checkambig=checkambig)
            f.write('FOO')
            f.close()

        # try some times, because reproduction of ambiguity depends on
        # "filesystem time"
        for i in xrange(5):
            atomicwrite(False)
            oldstat = os.stat(self._filename)
            if oldstat.st_ctime != oldstat.st_mtime:
                # subsequent changing never causes ambiguity
                continue

            repetition = 3

            # repeat atomic write with checkambig=True, to examine
            # whether st_mtime is advanced multiple times as expecetd
            for j in xrange(repetition):
                atomicwrite(True)
            newstat = os.stat(self._filename)
            if oldstat.st_ctime != newstat.st_ctime:
                # timestamp ambiguity was naturally avoided while repetition
                continue

            # st_mtime should be advanced "repetition" times, because
            # all atomicwrite() occured at same time (in sec)
            self.assertTrue(newstat.st_mtime ==
                            ((oldstat.st_mtime + repetition) & 0x7fffffff))
            # no more examination is needed, if assumption above is true
            break
        else:
            # This platform seems too slow to examine anti-ambiguity
            # of file timestamp (or test happened to be executed at
            # bad timing). Exit silently in this case, because running
            # on other faster platforms can detect problems
            pass

    def testread(self):
        with open(self._filename, 'wb') as f:
            f.write(b'foobar\n')
        file = atomictempfile(self._filename, mode='rb')
        self.assertTrue(file.read(), b'foobar\n')
        file.discard()

    def testcontextmanagersuccess(self):
        """When the context closes, the file is closed"""
        with atomictempfile('foo') as f:
            self.assertFalse(os.path.isfile('foo'))
            f.write(b'argh\n')
        self.assertTrue(os.path.isfile('foo'))

    def testcontextmanagerfailure(self):
        """On exception, the file is discarded"""
        try:
            with atomictempfile('foo') as f:
                self.assertFalse(os.path.isfile('foo'))
                f.write(b'argh\n')
                raise ValueError
        except ValueError:
            pass
        self.assertFalse(os.path.isfile('foo'))

if __name__ == '__main__':
    import silenttestrunner
    silenttestrunner.main(__name__)