tests/test_daklib_fstransactions.py

   1 #! /usr/bin/env python
   2 #
   3 # Copyright (C) 2012, Ansgar Burchardt <ansgar@debian.org>
   4 #
   5 # This program is free software; you can redistribute it and/or modify
   6 # it under the terms of the GNU General Public License as published by
   7 # the Free Software Foundation; either version 2 of the License, or
   8 # (at your option) any later version.
   9 #
  10 # This program is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 # GNU General Public License for more details.
  14 #
  15 # You should have received a copy of the GNU General Public License along
  16 # with this program; if not, write to the Free Software Foundation, Inc.,
  17 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18
  19 from base_test import DakTestCase
  20 from daklib.fstransactions import FilesystemTransaction
  21
  22 from unittest import main
  23
  24 import os
  25 import shutil
  26 import tempfile
  27
  28
  29 class TemporaryDirectory:
  30     def __init__(self):
  31         self.directory = None
  32     def __str__(self):
  33         return self.directory
  34     def filename(self, suffix):
  35         return os.path.join(self.directory, suffix)
  36     def __enter__(self):
  37         self.directory = tempfile.mkdtemp()
  38         return self
  39     def __exit__(self, *args):
  40         if self.directory is not None:
  41             shutil.rmtree(self.directory)
  42             self.directory = None
  43         return None
  44
  45 class FilesystemTransactionTestCase(DakTestCase):
  46     def _copy_a_b(self, tmp, fs, **kwargs):
  47         fs.copy(tmp.filename('a'), tmp.filename('b'), **kwargs)
  48
  49     def _write_to_a(self, tmp):
  50         with open(tmp.filename('a'), 'w') as fh:
  51             print >>fh, 'a'
  52
  53     def test_copy_non_existing(self):
  54         def copy():
  55             with TemporaryDirectory() as t:
  56                 with FilesystemTransaction() as fs:
  57                     self._copy_a_b(t, fs)
  58
  59         self.assertRaises(IOError, copy)
  60
  61     def test_copy_existing_and_commit(self):
  62         with TemporaryDirectory() as t:
  63             self._write_to_a(t)
  64
  65             with FilesystemTransaction() as fs:
  66                 self._copy_a_b(t, fs)
  67                 self.assert_(os.path.exists(t.filename('a')))
  68                 self.assert_(os.path.exists(t.filename('b')))
  69
  70             self.assert_(os.path.exists(t.filename('a')))
  71             self.assert_(os.path.exists(t.filename('b')))
  72
  73     def test_copy_existing_and_rollback(self):
  74         with TemporaryDirectory() as t:
  75             self._write_to_a(t)
  76
  77             class TestException(Exception):
  78                 pass
  79             try:
  80                 with FilesystemTransaction() as fs:
  81                     self._copy_a_b(t, fs)
  82                     self.assert_(os.path.exists(t.filename('a')))
  83                     self.assert_(os.path.exists(t.filename('b')))
  84                     raise TestException()
  85             except TestException:
  86                 pass
  87
  88             self.assert_(os.path.exists(t.filename('a')))
  89             self.assert_(not os.path.exists(t.filename('b')))
  90
  91     def test_unlink_and_commit(self):
  92         with TemporaryDirectory() as t:
  93             self._write_to_a(t)
  94             a = t.filename('a')
  95             with FilesystemTransaction() as fs:
  96                 self.assert_(os.path.exists(a))
  97                 fs.unlink(a)
  98                 self.assert_(not os.path.exists(a))
  99             self.assert_(not os.path.exists(a))
 100
 101     def test_unlink_and_rollback(self):
 102         with TemporaryDirectory() as t:
 103             self._write_to_a(t)
 104             a = t.filename('a')
 105             class TestException(Exception):
 106                 pass
 107
 108             try:
 109                 with FilesystemTransaction() as fs:
 110                     self.assert_(os.path.exists(a))
 111                     fs.unlink(a)
 112                     self.assert_(not os.path.exists(a))
 113                     raise TestException()
 114             except TestException:
 115                 pass
 116             self.assert_(os.path.exists(a))
 117
 118 if __name__ == '__main__':
 119     main()