proxy() does not play well with mock objects

[fatuhoku]

Execution completely freezes up when trying to get a proxy of an actor that's got a bit of constructor injection going on.

I'm specifically using Voidspace mock's MagicMock object:

# ...
mock_credit_card_processor = MagicMock()
foobar = Foobar.start(mock_credit_card_processor)
foobar.proxy()       # blocked indefinitely here!
# ...

... where the code to Foobar looks something like this:

class FooBar(pykka.ThreadingActor):
    def __init__(self, credit_card_processor):
        super(FooBar, self).__init__()
        self.credit_card_processor = credit_card_processor

I suspect because mock objects don't behave as pykka expects members to behave when doing introspection.

[jodal]

Yeah, there's a conflict between mock trying to please everything and provide any attribute asked for, and Pykka's proxy introspecting to figure out what attributes and methods are available. I haven't looked deeply into how to make them work better together, but I found a workaround: if you give your mock the real implementation as a spec then the mock object will only say it has attributes that the real implementation has as well, and not everything asked for.

To update your example:

# ...
mock_credit_card_processor = MagicMock(spec=RealCreditCardProcessor)
foobar = Foobar.start(mock_credit_card_processor, msg_captor)
foobar.proxy()
# ...

[fatuhoku]

Awesome, that's got me up and running again. Thanks @jodal .

[jodal]

I'll leave this open as a reminder to include it in a section on testing Pykka code.