~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2011, 2016 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

import threading

from bzrlib import (

    cethread,

    tests,

    )

class TestCatchingExceptionThread(tests.TestCase):

    def test_start_and_join_smoke_test(self):

        def do_nothing():

            pass

        tt = cethread.CatchingExceptionThread(target=do_nothing)

        tt.start()

        tt.join()

    def test_exception_is_re_raised(self):

        class MyException(Exception):

            pass

        def raise_my_exception():

            raise MyException()

        tt = cethread.CatchingExceptionThread(target=raise_my_exception)

        tt.start()

        self.assertRaises(MyException, tt.join)

    def test_join_around_exception(self):

        resume = threading.Event()

        class MyException(Exception):

            pass

        def raise_my_exception():

            # Wait for the test to tell us to resume

            resume.wait()

            # Now we can raise

            raise MyException()

        tt = cethread.CatchingExceptionThread(target=raise_my_exception)

        tt.start()

        tt.join(timeout=0)

        self.assertIs(None, tt.exception)

        resume.set()

        self.assertRaises(MyException, tt.join)

    def test_sync_event(self):

        control = threading.Event()

        in_thread = threading.Event()

        class MyException(Exception):

            pass

        def raise_my_exception():

            # Wait for the test to tell us to resume

            control.wait()

            # Now we can raise

            raise MyException()

        tt = cethread.CatchingExceptionThread(target=raise_my_exception,

                                            sync_event=in_thread)

        tt.start()

        tt.join(timeout=0)

        self.assertIs(None, tt.exception)

        self.assertIs(in_thread, tt.sync_event)

        control.set()

        self.assertRaises(MyException, tt.join)

        self.assertEqual(True, tt.sync_event.isSet())

    def test_switch_and_set(self):

        """Caller can precisely control a thread."""

        control1 = threading.Event()

        control2 = threading.Event()

        control3 = threading.Event()

        class TestThread(cethread.CatchingExceptionThread):

            def __init__(self):

                super(TestThread, self).__init__(target=self.step_by_step)

                self.current_step = 'starting'

                self.step1 = threading.Event()

                self.set_sync_event(self.step1)

                self.step2 = threading.Event()

                self.final = threading.Event()

            def step_by_step(self):

                control1.wait()

                self.current_step = 'step1'

                self.switch_and_set(self.step2)

                control2.wait()

                self.current_step = 'step2'

                self.switch_and_set(self.final)

                control3.wait()

                self.current_step = 'done'

        tt = TestThread()

        tt.start()

        self.assertEqual('starting', tt.current_step)

        control1.set()

        tt.step1.wait()

        self.assertEqual('step1', tt.current_step)

        control2.set()

        tt.step2.wait()

        self.assertEqual('step2', tt.current_step)

        control3.set()

        # We don't wait on tt.final

        tt.join()

        self.assertEqual('done', tt.current_step)

    def test_exception_while_switch_and_set(self):

        control1 = threading.Event()

        class MyException(Exception):

            pass

        class TestThread(cethread.CatchingExceptionThread):

            def __init__(self, *args, **kwargs):

                self.step1 = threading.Event()

                self.step2 = threading.Event()

                super(TestThread, self).__init__(target=self.step_by_step,

                                                 sync_event=self.step1)

                self.current_step = 'starting'

                self.set_sync_event(self.step1)

            def step_by_step(self):

                control1.wait()

                self.current_step = 'step1'

                self.switch_and_set(self.step2)

            def set_sync_event(self, event):

                # We force an exception while trying to set step2

                if event is self.step2:

                    raise MyException()

                super(TestThread, self).set_sync_event(event)

        tt = TestThread()

        tt.start()

        self.assertEqual('starting', tt.current_step)

        control1.set()

        # We now wait on step1 which will be set when catching the exception

        tt.step1.wait()

        self.assertRaises(MyException, tt.pending_exception)

        self.assertIs(tt.step1, tt.sync_event)

        self.assertTrue(tt.step1.isSet())