Hello.

The following workaround works fine for me:

    def setUp(self):
        self._sql_emitters = set()
        self.Base = create_base()
        self._create_db()
        # Moved BEFORE self.engine.connect()
        event.listen(
            self.engine,
            "before_cursor_execute",
            self._before_cursor_execute
        )
        self.connection = self.engine.connect()
        self.trans = self.connection.begin()
        self.session = Session(bind=self.connection, autoflush=False)

This way the new connection 'inherits' events from its parent engine.


Thank you again for your helpful assistance!

Ladislav Lenart


On 26.9.2012 19:29, Michael Bayer wrote:
> this is ticket #2575, only applies to 0.7 and not 0.8, and will be fixed 
> today.
> 
> In the meantime, please use the format that I gave you - a single, fixed 
> event listener on the Engine class, established at the module level.  The 
> assertion logic then subscribes a "listen" function inside a collection 
> accessed by the event listener.
> 
> 
> 
> On Sep 26, 2012, at 1:19 PM, Ladislav Lenart wrote:
> 
>> Hello.
>>
>> Call to event.listen(self.connection,...) fails with:
>>
>>    InvalidRequestError: No such event 'before_cursor_execute' for target...
>>
>> because self.connection does not have 'dispatch' attribute:
>>
>>    def listen(target, identifier, fn, *args, **kw):
>>        for evt_cls in _registrars[identifier]:
>>            # A target must have dispatch attribute as required
>>            # by Events._accept_with class method.
>>            tgt = evt_cls._accept_with(target)
>>            if tgt is not None:
>>                tgt.dispatch._listen(tgt, identifier, fn, *args, **kw)
>>                return
>>        raise exc.InvalidRequestError("No such event '%s' for target '%s'" %
>>
>> As I have written, the only two objects in the setUp method that the function
>> event.listen accepts are self.engine and type(self.engine).
>>
>> Any other idea what am I doing wrong?
>>
>> Ladislav Lenart
>>
>>
>> On 26.9.2012 19:07, Michael Bayer wrote:
>>>
>>> On Sep 26, 2012, at 12:36 PM, Ladislav Lenart wrote:
>>>
>>>> Hello.
>>>>
>>>>> I can guarantee you all SQL goes through the same channels.
>>>>
>>>> No doubts there :-)
>>>>
>>>>
>>>>> perhaps you registered the event with a specific Engine or Connection 
>>>>> that is
>>>> not the one involved in the test.
>>>>
>>>> This might be it, but I don't know what should I supply instead. I have the
>>>> following setUp:
>>>>
>>>> class DbTestCase(object):
>>>>   def setUp(self):
>>>>       self.Base = create_base()
>>>>       self._create_db()
>>>>       self.connection = self.engine.connect()
>>>>       self.trans = self.connection.begin()
>>>>       self.session = Session(bind=self.connection, autoflush=False)
>>>>       self._sql_emitters = set()
>>>>       event.listen(
>>>>           self.engine,
>>>>           "before_cursor_execute",
>>>>           self._before_cursor_execute
>>>>       )
>>>>
>>>> I have tried every object (and its type) present in the setUp method, but 
>>>> all
>>>> fail with
>>>>
>>>>   InvalidRequestError: No such event 'before_cursor_execute' for target...
>>>
>>> you've got self.connection already.   so you want to listen on that:
>>>
>>> event.listen(self.connection, ...)
>>>
>>> when a Connection is constructed, it takes a snapshot of the event 
>>> listeners associated with its parent Engine.    This is for performance 
>>> reasons so that event dispatch doesn't need to check two separate dispatch 
>>> collections.
>>>
>>>
>>
>>
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