09.12.2019 18:10, Max Reitz wrote:
> On 03.12.19 13:59, Vladimir Sementsov-Ogievskiy wrote:
>> 11.11.2019 19:02, Max Reitz wrote:
>>> Signed-off-by: Max Reitz <mre...@redhat.com>
>>> ---
>>> tests/qemu-iotests/iotests.py | 59 +++++++++++++++++++++++++++++++++++
>>> 1 file changed, 59 insertions(+)
>>>
>>> diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
>>> index d34305ce69..3e03320ce3 100644
>>> --- a/tests/qemu-iotests/iotests.py
>>> +++ b/tests/qemu-iotests/iotests.py
>>> @@ -681,6 +681,65 @@ class VM(qtest.QEMUQtestMachine):
>>>
>>> return fields.items() <= ret.items()
>>>
>>> + """
>>> + Check whether the node under the given path in the block graph is
>>> + @expected_node.
>>> +
>>> + @root is the node name of the node where the @path is rooted.
>>> +
>>> + @path is a string that consists of child names separated by
>>> + slashes. It must begin with a slash.
>>
>> Why do you need this slash?
>
> I don’t. It just looked better to me.
>
> (One reason would be so it could be empty to refer to @root, but as I
> said that isn’t very useful.)
>
>> To stress that we are starting from root?
>> But root is not global, it's selected by previous argument, so for me the
>> path is more like relative than absolute..
>>
>>> +
>>> + Examples for @root + @path:
>>> + - root="qcow2-node", path="/backing/file"
>>> + - root="quorum-node", path="/children.2/file"
>>> +
>>> + Hypothetically, @path could be empty, in which case it would point
>>> + to @root. However, in practice this case is not useful and hence
>>> + not allowed.
>>
>> 1. path can't be empty, as accordingly to previous point, it must start with
>> '/'
>
> Hence “hypothetically”.
>
>> 2. path can be '/', which does exactly what you don't allow, and I don't see,
>> where it is restricted in code
>
> No, it doesn’t. That refers to a child of @root with an empty name.
Hmm, yes, OK.
>
>>> +
>>> + @expected_node may be None.
>>
>> Which means that, we assert existence of the path except its last element,
>> yes? Worth mention this behavior here.
>
> “(All elements of the path but the leaf must still exist.)”? OK.
OK
>
>>> +
>>> + @graph may be None or the result of an x-debug-query-block-graph
>>> + call that has already been performed.
>>> + """
>>> + def assert_block_path(self, root, path, expected_node, graph=None):
>>> + if graph is None:
>>> + graph = self.qmp('x-debug-query-block-graph')['return']
>>> +
>>> + iter_path = iter(path.split('/'))
>>> +
>>> + # Must start with a /
>>> + assert next(iter_path) == ''
>>> +
>>> + node = next((node for node in graph['nodes'] if node['name'] ==
>>> root),
>>> + None)
>>> +
>>> + for path_node in iter_path:
>>> + assert node is not None, 'Cannot follow path %s' % path
>>> +
>>> + try:
>>> + node_id = next(edge['child'] for edge in graph['edges'] \
>>> + if edge['parent'] ==
>>> node['id'] and
>>> + edge['name'] == path_node)
>>> +
>>> + node = next(node for node in graph['nodes'] \
>>> + if node['id'] == node_id)
>>
>> this line cant fail. If it fail, it means a bug in
>> x-debug-query-block-graph, so,
>> I'd prefer to move it out of try:except block.
>
> But that makes the code uglier, in my opinion. We’d then have to set
> node_id to e.g. None in the except branch (or rather just abolish the
> try-except then) and check whether it’s None before assigning node.
> Like this:
>
> node_id = next(..., None)
>
> if node_id is not None:
> node = next(...)
> else:
> node = None
>
> I prefer the current try-except construct over that.
OK
>
>>> + except StopIteration:
>>> + node = None
>>> +
>>> + assert node is not None or expected_node is None, \
>>> + 'No node found under %s (but expected %s)' % \
>>> + (path, expected_node)
>>> +
>>> + assert expected_node is not None or node is None, \
>>> + 'Found node %s under %s (but expected none)' % \
>>> + (node['name'], path)
>>> +
>>> + if node is not None and expected_node is not None:
>>
>> [1]
>> second part of condition already asserted by previous assertion
>
> Yes, but I wanted to cover all four cases explicitly. (In the usual 00,
> 01, 10, 11 manner. Well, except it’s 10, 01, 11, 00.)
>
>>> + assert node['name'] == expected_node, \
>>> + 'Found node %s under %s (but expected %s)' % \
>>> + (node['name'], path, expected_node)
>>
>> IMHO, it would be easier to read like:
>>
>> if node is None:
>> assert expected_node is None, \
>> 'No node found under %s (but expected %s)' % \
>> (path, expected_node)
>> else:
>> assert expected_node is not None, \
>> 'Found node %s under %s (but expected none)' % \
>> (node['name'], path)
>>
>> assert node['name'] == expected_node, \
>> 'Found node %s under %s (but expected %s)' % \
>> (node['name'], path, expected_node)
>>
>> Or even just
>>
>> if node is None:
>> assert expected_node is None, \
>> 'No node found under %s (but expected %s)' % \
>> (path, expected_node)
>> else:
>> assert node['name'] == expected_node, \
>> 'Found node %s under %s (but expected %s)' % \
>> (node['name'], path, expected_node)
>
> Works for me, too.
>
>> (I've checked:
>> >>> 'erger %s erg' % None
>> 'erger None erg'
>>
>> Also, %-style formatting is old, as I understand it's better always use
>> .format()
>> )
>
> OK.
>
> Max
>
>>>
>>> index_re = re.compile(r'([^\[]+)\[([^\]]+)\]')
>>>
>>>
>
>
--
Best regards,
Vladimir
