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Viewing changes to bzrlib/tests/test_counted_lock.py

  • Committer: Alexander Belchenko
  • Date: 2006-07-30 16:43:12 UTC
  • mto: (1711.2.111 jam-integration)
  • mto: This revision was merged to the branch mainline in revision 1906.
  • Revision ID: bialix@ukr.net-20060730164312-b025fd3ff0cee59e
rename  gpl.txt => COPYING.txt

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bzrlib/tests/test_counted_lock.py
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# Copyright (C) 2007, 2008, 2009 Canonical Ltd
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
7
 
#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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# GNU General Public License for more details.
12
 
#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
15
 
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
16
 
 
17
 
"""Tests for bzrlib.counted_lock"""
18
 
 
19
 
from bzrlib.counted_lock import CountedLock
20
 
from bzrlib.errors import (
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    LockError,
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    LockNotHeld,
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    ReadOnlyError,
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    TokenMismatch,
25
 
    )
26
 
from bzrlib.tests import TestCase
27
 
 
28
 
 
29
 
class DummyLock(object):
30
 
    """Lock that just records what's been done to it."""
31
 
 
32
 
    def __init__(self):
33
 
        self._calls = []
34
 
        self._lock_mode = None
35
 
 
36
 
    def is_locked(self):
37
 
        return self._lock_mode is not None
38
 
 
39
 
    def lock_read(self):
40
 
        self._assert_not_locked()
41
 
        self._lock_mode = 'r'
42
 
        self._calls.append('lock_read')
43
 
 
44
 
    def lock_write(self, token=None):
45
 
        if token is not None:
46
 
            if token == 'token':
47
 
                # already held by this caller
48
 
                return 'token'
49
 
            else:
50
 
                raise TokenMismatch()
51
 
        self._assert_not_locked()
52
 
        self._lock_mode = 'w'
53
 
        self._calls.append('lock_write')
54
 
        return 'token'
55
 
 
56
 
    def unlock(self):
57
 
        self._assert_locked()
58
 
        self._lock_mode = None
59
 
        self._calls.append('unlock')
60
 
 
61
 
    def break_lock(self):
62
 
        self._lock_mode = None
63
 
        self._calls.append('break')
64
 
 
65
 
    def _assert_locked(self):
66
 
        if not self._lock_mode:
67
 
            raise LockError("%s is not locked" % (self,))
68
 
 
69
 
    def _assert_not_locked(self):
70
 
        if self._lock_mode:
71
 
            raise LockError("%s is already locked in mode %r" %
72
 
                (self, self._lock_mode))
73
 
 
74
 
    def validate_token(self, token):
75
 
        if token == 'token':
76
 
            # already held by this caller
77
 
            return 'token'
78
 
        elif token is None:
79
 
            return
80
 
        else:
81
 
            raise TokenMismatch(token, 'token')
82
 
 
83
 
 
84
 
class TestDummyLock(TestCase):
85
 
 
86
 
    def test_lock_initially_not_held(self):
87
 
        l = DummyLock()
88
 
        self.assertFalse(l.is_locked())
89
 
 
90
 
    def test_lock_not_reentrant(self):
91
 
        # can't take the underlying lock twice
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        l = DummyLock()
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        l.lock_read()
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        self.assertRaises(LockError, l.lock_read)
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96
 
    def test_detect_underlock(self):
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        l = DummyLock()
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        self.assertRaises(LockError, l.unlock)
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100
 
    def test_basic_locking(self):
101
 
        # dummy lock works like a basic non reentrant lock
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        real_lock = DummyLock()
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        self.assertFalse(real_lock.is_locked())
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        # lock read and unlock
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        real_lock.lock_read()
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        self.assertTrue(real_lock.is_locked())
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        real_lock.unlock()
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        self.assertFalse(real_lock.is_locked())
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        # lock write and unlock
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        result = real_lock.lock_write()
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        self.assertEqual('token', result)
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        self.assertTrue(real_lock.is_locked())
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        real_lock.unlock()
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        self.assertFalse(real_lock.is_locked())
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        # check calls
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        self.assertEqual(
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            ['lock_read', 'unlock', 'lock_write', 'unlock'],
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            real_lock._calls)
119
 
 
120
 
    def test_break_lock(self):
121
 
        l = DummyLock()
122
 
        l.lock_write()
123
 
        l.break_lock()
124
 
        self.assertFalse(l.is_locked())
125
 
        self.assertEqual(
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            ['lock_write', 'break'],
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            l._calls)
128
 
 
129
 
 
130
 
class TestCountedLock(TestCase):
131
 
 
132
 
    def test_read_lock(self):
133
 
        # Lock and unlock a counted lock
134
 
        real_lock = DummyLock()
135
 
        l = CountedLock(real_lock)
136
 
        self.assertFalse(l.is_locked())
137
 
        # can lock twice, although this isn't allowed on the underlying lock
138
 
        l.lock_read()
139
 
        l.lock_read()
140
 
        self.assertTrue(l.is_locked())
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        # and release
142
 
        l.unlock()
143
 
        self.assertTrue(l.is_locked())
144
 
        l.unlock()
145
 
        self.assertFalse(l.is_locked())
146
 
        self.assertEquals(
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            ['lock_read', 'unlock'],
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            real_lock._calls)
149
 
 
150
 
    def test_unlock_not_locked(self):
151
 
        real_lock = DummyLock()
152
 
        l = CountedLock(real_lock)
153
 
        self.assertRaises(LockNotHeld, l.unlock)
154
 
 
155
 
    def test_read_lock_while_write_locked(self):
156
 
        real_lock = DummyLock()
157
 
        l = CountedLock(real_lock)
158
 
        l.lock_write()
159
 
        l.lock_read()
160
 
        self.assertEquals('token', l.lock_write())
161
 
        l.unlock()
162
 
        l.unlock()
163
 
        l.unlock()
164
 
        self.assertFalse(l.is_locked())
165
 
        self.assertEquals(
166
 
            ['lock_write', 'unlock'],
167
 
            real_lock._calls)
168
 
 
169
 
    def test_write_lock_while_read_locked(self):
170
 
        real_lock = DummyLock()
171
 
        l = CountedLock(real_lock)
172
 
        l.lock_read()
173
 
        self.assertRaises(ReadOnlyError, l.lock_write)
174
 
        self.assertRaises(ReadOnlyError, l.lock_write)
175
 
        l.unlock()
176
 
        self.assertFalse(l.is_locked())
177
 
        self.assertEquals(
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            ['lock_read', 'unlock'],
179
 
            real_lock._calls)
180
 
 
181
 
    def test_write_lock_reentrant(self):
182
 
        real_lock = DummyLock()
183
 
        l = CountedLock(real_lock)
184
 
        self.assertEqual('token', l.lock_write())
185
 
        self.assertEqual('token', l.lock_write())
186
 
        l.unlock()
187
 
        l.unlock()
188
 
 
189
 
    def test_reenter_with_token(self):
190
 
        real_lock = DummyLock()
191
 
        l1 = CountedLock(real_lock)
192
 
        l2 = CountedLock(real_lock)
193
 
        token = l1.lock_write()
194
 
        self.assertEqual('token', token)
195
 
        # now imagine that we lost that connection, but we still have the
196
 
        # token...
197
 
        del l1
198
 
        # because we can supply the token, we can acquire the lock through
199
 
        # another instance
200
 
        self.assertTrue(real_lock.is_locked())
201
 
        self.assertFalse(l2.is_locked())
202
 
        self.assertEqual(token, l2.lock_write(token=token))
203
 
        self.assertTrue(l2.is_locked())
204
 
        self.assertTrue(real_lock.is_locked())
205
 
        l2.unlock()
206
 
        self.assertFalse(l2.is_locked())
207
 
        self.assertFalse(real_lock.is_locked())
208
 
 
209
 
    def test_break_lock(self):
210
 
        real_lock = DummyLock()
211
 
        l = CountedLock(real_lock)
212
 
        l.lock_write()
213
 
        l.lock_write()
214
 
        self.assertTrue(real_lock.is_locked())
215
 
        l.break_lock()
216
 
        self.assertFalse(l.is_locked())
217
 
        self.assertFalse(real_lock.is_locked())
218
 
 
219
 
    # TODO: test get_physical_lock_status