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Viewing changes to bzrlib/tests/test_thread.py

  • Committer: Vincent Ladeuil
  • Date: 2011-02-10 11:49:48 UTC
  • mto: This revision was merged to the branch mainline in revision 5661.
  • Revision ID: v.ladeuil+lp@free.fr-20110210114948-hktri36s9tk0kdj0
Add CatchingExceptionThread.set_and_switch() to avoid race conditions.

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Lines of Context:
bzrlib/tests/test_thread.py
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        tt.start()
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        self.assertRaises(MyException, tt.join)
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    def test_join_when_no_exception(self):
 
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    def test_join_around_exception(self):
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        resume = threading.Event()
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        class MyException(Exception):
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            pass
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        resume.set()
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        self.assertRaises(MyException, tt.join)
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    def test_sync_event(self):
 
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        control = threading.Event()
 
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        in_thread = threading.Event()
 
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        class MyException(Exception):
 
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            pass
 
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        def raise_my_exception():
 
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            # Wait for the test to tell us to resume
 
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            control.wait()
 
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            # Now we can raise
 
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            raise MyException()
 
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        tt = thread.CatchingExceptionThread(target=raise_my_exception,
 
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                                            sync_event=in_thread)
 
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        tt.start()
 
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        tt.join(timeout=0)
 
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        self.assertIs(None, tt.exception)
 
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        self.assertIs(in_thread, tt.sync_event)
 
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        control.set()
 
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        self.assertRaises(MyException, tt.join)
 
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        self.assertEquals(True, tt.sync_event.isSet())
 
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    def test_set_and_switch(self):
 
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        """Caller can precisely control a thread."""
 
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        control1 = threading.Event()
 
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        control2 = threading.Event()
 
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        control3 = threading.Event()
 
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        class TestThread(thread.CatchingExceptionThread):
 
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            def __init__(self, *args, **kwargs):
 
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                super(TestThread, self).__init__(*args,
 
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                                                 target=self.step_by_step,
 
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                                                 **kwargs)
 
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                self.current_step = 'starting'
 
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                self.step1 = threading.Event()
 
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                self.set_sync_event(self.step1)
 
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                self.step2 = threading.Event()
 
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                self.final = threading.Event()
 
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            def step_by_step(self):
 
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                control1.wait()
 
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                self.current_step = 'step1'
 
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                self.set_and_switch(self.step2)
 
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                control2.wait()
 
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                self.current_step = 'step2'
 
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                self.set_and_switch(self.final)
 
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                control3.wait()
 
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                self.current_step = 'done'
 
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        tt = TestThread()
 
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        tt.start()
 
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        self.assertEquals('starting', tt.current_step)
 
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        control1.set()
 
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        tt.step1.wait()
 
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        self.assertEquals('step1', tt.current_step)
 
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        control2.set()
 
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        tt.step2.wait()
 
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        self.assertEquals('step2', tt.current_step)
 
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        control3.set()
 
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        # We don't wait on tt.final
 
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        tt.join()
 
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        self.assertEquals('done', tt.current_step)
 
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    def test_exception_while_set_and_switch(self):
 
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        control1 = threading.Event()
 
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        class MyException(Exception):
 
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            pass
 
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        class TestThread(thread.CatchingExceptionThread):
 
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            def __init__(self, *args, **kwargs):
 
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                self.step1 = threading.Event()
 
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                self.step2 = threading.Event()
 
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                super(TestThread, self).__init__(*args,
 
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                                                 target=self.step_by_step,
 
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                                                  sync_event=self.step1,
 
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                                                 **kwargs)
 
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                self.current_step = 'starting'
 
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                self.set_sync_event(self.step1)
 
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            def step_by_step(self):
 
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                control1.wait()
 
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                self.current_step = 'step1'
 
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                self.set_and_switch(self.step2)
 
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            def set_sync_event(self, event):
 
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                # We force an exception while trying to set step2
 
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                if event is self.step2:
 
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                    raise MyException()
 
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                super(TestThread, self).set_sync_event(event)
 
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        tt = TestThread()
 
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        tt.start()
 
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        self.assertEquals('starting', tt.current_step)
 
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        control1.set()
 
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        # We now wait on step1 which will be set when catching the exception
 
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        tt.step1.wait()
 
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        self.assertRaises(MyException, tt.pending_exception)
 
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        self.assertIs(tt.step1, tt.sync_event)
 
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        self.assertTrue(tt.step1.isSet())