Re: [Qemu-devel] [PATCH 4/4] iotests: Add test for failing mirror complete

[Max Reitz <mreitz@redhat.com>]

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On 19.09.19 19:02, John Snow wrote:
> 
> 
> On 9/19/19 12:58 PM, Max Reitz wrote:
>> On 18.09.19 20:46, John Snow wrote:
>>>
>>>
>>> On 9/12/19 9:56 AM, Max Reitz wrote:
>>>> Signed-off-by: Max Reitz <mreitz@redhat.com>
>>>> ---
>>>>   tests/qemu-iotests/041     | 44 ++++++++++++++++++++++++++++++++++++++
>>>>   tests/qemu-iotests/041.out |  4 ++--
>>>>   2 files changed, 46 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/tests/qemu-iotests/041 b/tests/qemu-iotests/041
>>>> index 8568426311..84bc6d6581 100755
>>>> --- a/tests/qemu-iotests/041
>>>> +++ b/tests/qemu-iotests/041
>>>> @@ -1121,6 +1121,50 @@ class TestOrphanedSource(iotests.QMPTestCase):
>>>>                                target='dest-ro')
>>>>           self.assert_qmp(result, 'error/class', 'GenericError')
>>>>   +    def test_failing_permission_in_complete(self):
>>>> +        self.assert_no_active_block_jobs()
>>>> +
>>>> +        # Unshare consistent-read on the target
>>>> +        # (The mirror job does not care)
>>>> +        result = self.vm.qmp('blockdev-add',
>>>> +                             driver='blkdebug',
>>>> +                             node_name='dest-perm',
>>>> +                             image='dest',
>>>> +                             unshare_child_perms=['consistent-read'])
>>>> +        self.assert_qmp(result, 'return', {})
>>>> +
>>>> +        result = self.vm.qmp('blockdev-mirror', job_id='job',
>>>> device='src',
>>>> +                             sync='full', target='dest',
>>>> +                             filter_node_name='mirror-filter')
>>>> +        self.assert_qmp(result, 'return', {})
>>>> +
>>>> +        # Require consistent-read on the source
>>>> +        # (We can only add this node once the job has started, or it
>>>> +        # will complain that it does not want to run on non-root nodes)
>>>> +        result = self.vm.qmp('blockdev-add',
>>>> +                             driver='blkdebug',
>>>> +                             node_name='src-perm',
>>>> +                             image='src',
>>>> +                             take_child_perms=['consistent-read'])
>>>> +        self.assert_qmp(result, 'return', {})
>>>> +
>>>> +        # While completing, mirror will attempt to replace src by
>>>> +        # dest, which must fail because src-perm requires
>>>> +        # consistent-read but dest-perm does not share it; thus
>>>> +        # aborting the job when it is supposed to complete
>>>> +        self.complete_and_wait('job',
>>>> +                               completion_error='Operation not
>>>> permitted')
>>>> +
>>>> +        # Assert that all of our nodes are still there (except for the
>>>> +        # mirror filter, which should be gone despite the failure)
>>>> +        nodes = self.vm.qmp('query-named-block-nodes')['return']
>>>> +        nodes = list(map(lambda image: image['node-name'], nodes))
>>>
>>> Sadly, the list comprehension is a good suggestion. Squash it in if
>>> you'd like.
>>
>> You know I don’t, but I’ll do it anyway.
>>
> 
> Don't you dare make me feel bad by re-spinning, though.

I have to respin anyway. ;-)

>>>> +
>>>> +        for expect in ['src', 'src-perm', 'dest', 'dest-perm']:
>>>> +            self.assertTrue(expect in nodes, '%s disappeared' % expect)
>>>
>>> I could be a real weenie and say "why not use a tuple here?"
>>
>> OK.
>>
>>> but, I'll only pretend I didn't say that instead of couching it in a
>>> self-deprecating wrapper to the same end effect.
>>>
>>> (I'm a weenie.)
>>>
>>>> +        self.assertFalse('mirror-filter' in nodes,
>>>> +                         'Mirror filter node did not disappear')
>>>> +
>>>>   if __name__ == '__main__':
>>>>       iotests.main(supported_fmts=['qcow2', 'qed'],
>>>>                    supported_protocols=['file'])
>>>> diff --git a/tests/qemu-iotests/041.out b/tests/qemu-iotests/041.out
>>>> index 2c448b4239..f496be9197 100644
>>>> --- a/tests/qemu-iotests/041.out
>>>> +++ b/tests/qemu-iotests/041.out
>>>> @@ -1,5 +1,5 @@
>>>> -..........................................................................................
>>>>
>>>> +...........................................................................................
>>>>
>>>>   ----------------------------------------------------------------------
>>>> -Ran 90 tests
>>>> +Ran 91 tests
>>>>     OK
>>>>
>>>
>>> Or don't do anything, because I'm just being obnoxious, and I owe you
>>> one for giving you bad advice last round.
>>
>> Come on, I have better (more selfish) reasons.
>>
>> For the list comprehension: I want to introduce as many instances of
>> map/filter as I can so using those functions becomes normal.
>>
> 
> They have their uses! But also they're usually just simply longer and
> aren't worth using where list comprehensions do.

The point is that they’re special language constructs whereas map/filter
are available in basically any decent language.

>> For the tuple: This is a test, nobody cares whether it uses 60 bytes
>> more memory or is 10 µs slower or lets something be mutable when it is
>> actually never changed.  As such, I like to use the most general
>> solution which is simply a list.
>>
> 
> I did say I was being a weenie. You really can take the reviewed-by!

I’m just saying those would be my reasons if I rejected the changes
suggested by you both.  I don’t reject them, though. :-)

Max


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