~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2009 Canonical Ltd

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

from cStringIO import StringIO

import re

from bzrlib.cleanup import (

    _do_with_cleanups,

    _run_cleanup,

    OperationWithCleanups,

    )

from bzrlib.tests import TestCase

from bzrlib import (

    debug,

    trace,

    )

class CleanupsTestCase(TestCase):

    def setUp(self):

        super(CleanupsTestCase, self).setUp()

        self.call_log = []

    def no_op_cleanup(self):

        self.call_log.append('no_op_cleanup')

    def assertLogContains(self, regex):

        self.assertContainsRe(self.get_log(), regex, re.DOTALL)

    def failing_cleanup(self):

        self.call_log.append('failing_cleanup')

        raise Exception("failing_cleanup goes boom!")

class TestRunCleanup(CleanupsTestCase):

    def test_no_errors(self):

        """The function passed to _run_cleanup is run."""

        self.assertTrue(_run_cleanup(self.no_op_cleanup))

        self.assertEqual(['no_op_cleanup'], self.call_log)

    def test_cleanup_with_args_kwargs(self):

        def func_taking_args_kwargs(*args, **kwargs):

            self.call_log.append(('func', args, kwargs))

        _run_cleanup(func_taking_args_kwargs, 'an arg', kwarg='foo')

        self.assertEqual(

            [('func', ('an arg',), {'kwarg': 'foo'})], self.call_log)

    def test_cleanup_error(self):

        """An error from the cleanup function is logged by _run_cleanup, but not

        propagated.

        This is there's no way for _run_cleanup to know if there's an existing

        exception in this situation::

            try:

              some_func()

            finally:

              _run_cleanup(cleanup_func)

        So, the best _run_cleanup can do is always log errors but never raise

        them.

        """

        self.assertFalse(_run_cleanup(self.failing_cleanup))

        self.assertLogContains('Cleanup failed:.*failing_cleanup goes boom')

    def test_cleanup_error_debug_flag(self):

        """The -Dcleanup debug flag causes cleanup errors to be reported to the

        user.

        """

        log = StringIO()

        trace.push_log_file(log)

        debug.debug_flags.add('cleanup')

        self.assertFalse(_run_cleanup(self.failing_cleanup))

        self.assertContainsRe(

            log.getvalue(),

            "bzr: warning: Cleanup failed:.*failing_cleanup goes boom")

    def test_prior_error_cleanup_succeeds(self):

        """Calling _run_cleanup from a finally block will not interfere with an

        exception from the try block.

        """

        def failing_operation():

            try:

                1/0

            finally:

                _run_cleanup(self.no_op_cleanup)

        self.assertRaises(ZeroDivisionError, failing_operation)

        self.assertEqual(['no_op_cleanup'], self.call_log)

    def test_prior_error_cleanup_fails(self):

        """Calling _run_cleanup from a finally block will not interfere with an

        exception from the try block even when the cleanup itself raises an

        exception.

        The cleanup exception will be logged.

        """

        def failing_operation():

            try:

                1/0

            finally:

                _run_cleanup(self.failing_cleanup)

        self.assertRaises(ZeroDivisionError, failing_operation)

        self.assertLogContains('Cleanup failed:.*failing_cleanup goes boom')

class TestDoWithCleanups(CleanupsTestCase):

    def trivial_func(self):

        self.call_log.append('trivial_func')

        return 'trivial result'

    def test_runs_func(self):

        """_do_with_cleanups runs the function it is given, and returns the

        result.

        """

        result = _do_with_cleanups([], self.trivial_func)

        self.assertEqual('trivial result', result)

    def test_runs_cleanups(self):

        """Cleanup functions are run (in the given order)."""

        cleanup_func_1 = (self.call_log.append, ('cleanup 1',), {})

        cleanup_func_2 = (self.call_log.append, ('cleanup 2',), {})

        _do_with_cleanups([cleanup_func_1, cleanup_func_2], self.trivial_func)

        self.assertEqual(

            ['trivial_func', 'cleanup 1', 'cleanup 2'], self.call_log)

    def failing_func(self):

        self.call_log.append('failing_func')

        1/0

    def test_func_error_propagates(self):

        """Errors from the main function are propagated (after running

        cleanups).

        """

        self.assertRaises(

            ZeroDivisionError, _do_with_cleanups,

            [(self.no_op_cleanup, (), {})], self.failing_func)

        self.assertEqual(['failing_func', 'no_op_cleanup'], self.call_log)

    def test_func_error_trumps_cleanup_error(self):

        """Errors from the main function a propagated even if a cleanup raises

        an error.

        The cleanup error is be logged.

        """

        self.assertRaises(

            ZeroDivisionError, _do_with_cleanups,

            [(self.failing_cleanup, (), {})], self.failing_func)

        self.assertLogContains('Cleanup failed:.*failing_cleanup goes boom')

    def test_func_passes_and_error_from_cleanup(self):

        """An error from a cleanup is propagated when the main function doesn't

        raise an error.  Later cleanups are still executed.

        """

        exc = self.assertRaises(

            Exception, _do_with_cleanups,

            [(self.failing_cleanup, (), {}), (self.no_op_cleanup, (), {})],

            self.trivial_func)

        self.assertEqual('failing_cleanup goes boom!', exc.args[0])

        self.assertEqual(

            ['trivial_func', 'failing_cleanup', 'no_op_cleanup'],

            self.call_log)

    def test_multiple_cleanup_failures(self):

        """When multiple cleanups fail (as tends to happen when something has

        gone wrong), the first error is propagated, and subsequent errors are

        logged.

        """

        cleanups = self.make_two_failing_cleanup_funcs()

        self.assertRaises(ErrorA, _do_with_cleanups, cleanups,

            self.trivial_func)

        self.assertLogContains('Cleanup failed:.*ErrorB')

        self.assertFalse('ErrorA' in self.get_log())

    def make_two_failing_cleanup_funcs(self):

        def raise_a():

            raise ErrorA('Error A')

        def raise_b():

            raise ErrorB('Error B')

        return [(raise_a, (), {}), (raise_b, (), {})]

    def test_multiple_cleanup_failures_debug_flag(self):

        log = StringIO()

        trace.push_log_file(log)

        debug.debug_flags.add('cleanup')

        cleanups = self.make_two_failing_cleanup_funcs()

        self.assertRaises(ErrorA, _do_with_cleanups, cleanups,

            self.trivial_func)

        self.assertContainsRe(

            log.getvalue(), "bzr: warning: Cleanup failed:.*Error B\n")

        self.assertEqual(1, log.getvalue().count('bzr: warning:'),

                log.getvalue())

    def test_func_and_cleanup_errors_debug_flag(self):

        log = StringIO()

        trace.push_log_file(log)

        debug.debug_flags.add('cleanup')

        cleanups = self.make_two_failing_cleanup_funcs()

        self.assertRaises(ZeroDivisionError, _do_with_cleanups, cleanups,

            self.failing_func)

        self.assertContainsRe(

            log.getvalue(), "bzr: warning: Cleanup failed:.*Error A\n")

        self.assertContainsRe(

            log.getvalue(), "bzr: warning: Cleanup failed:.*Error B\n")

        self.assertEqual(2, log.getvalue().count('bzr: warning:'))

    def test_func_may_mutate_cleanups(self):

        """The main func may mutate the cleanups before it returns.

        This allows a function to gradually add cleanups as it acquires

        resources, rather than planning all the cleanups up-front.  The

        OperationWithCleanups helper relies on this working.

        """

        cleanups_list = []

        def func_that_adds_cleanups():

            self.call_log.append('func_that_adds_cleanups')

            cleanups_list.append((self.no_op_cleanup, (), {}))

            return 'result'

        result = _do_with_cleanups(cleanups_list, func_that_adds_cleanups)

        self.assertEqual('result', result)

        self.assertEqual(

            ['func_that_adds_cleanups', 'no_op_cleanup'], self.call_log)

    def test_cleanup_error_debug_flag(self):

        """The -Dcleanup debug flag causes cleanup errors to be reported to the

        user.

        """

        log = StringIO()

        trace.push_log_file(log)

        debug.debug_flags.add('cleanup')

        self.assertRaises(ZeroDivisionError, _do_with_cleanups,

            [(self.failing_cleanup, (), {})], self.failing_func)

        self.assertContainsRe(

            log.getvalue(),

            "bzr: warning: Cleanup failed:.*failing_cleanup goes boom")

        self.assertEqual(1, log.getvalue().count('bzr: warning:'))

class ErrorA(Exception): pass

class ErrorB(Exception): pass

class TestOperationWithCleanups(CleanupsTestCase):

    def test_cleanup_ordering(self):

        """Cleanups are added in LIFO order.

        So cleanups added before run is called are run last, and the last

        cleanup added during the func is run first.

        """

        call_log = []

        def func(op, foo):

            call_log.append(('func called', foo))

            op.add_cleanup(call_log.append, 'cleanup 2')

            op.add_cleanup(call_log.append, 'cleanup 1')

            return 'result'

        owc = OperationWithCleanups(func)

        owc.add_cleanup(call_log.append, 'cleanup 4')

        owc.add_cleanup(call_log.append, 'cleanup 3')

        result = owc.run('foo')

        self.assertEqual('result', result)

        self.assertEqual(

            [('func called', 'foo'), 'cleanup 1', 'cleanup 2', 'cleanup 3',

            'cleanup 4'], call_log)