From: Jeremy Bopp <jeremy@...>
Date: 2010-11-03T23:20:12+09:00
Subject: Re: Inversion of Control in Ruby by passing classes - does it make any sense?

On 11/3/2010 9:06 AM, Robert Klemme wrote:
> On Wed, Nov 3, 2010 at 3:00 PM, Jeremy Bopp <jeremy@bopp.net> wrote:
>> On 11/3/2010 5:20 AM, Robert Klemme wrote:
>>> On Tue, Nov 2, 2010 at 9:29 PM, Jeremy Bopp <jeremy@bopp.net> wrote:
>>>> What I'm about to suggest will generate warnings from Ruby and is
>>>> probably not the "best" way, but you could also replace OtherClass with
>>>> your MockLoggerClass with a simple assignment during your test:
>>>>
>>>> OtherClass = MockLoggerClass  # This generates a warning...
>>>> s = SomeClass.new
>>>> s.do_something(1, 2)
>>>
>>> This is not exactly the same as it does not allow control over the
>>> created instance per instance.  You basically change global state vs.
>>> Manuel's approach with local state.
>>
>> I agree, but I was approaching this from a minimal unit test standpoint
>> rather than a generally applicable part of Manuel's design.  Would you
>> say that changing the global state in this way or in the other way I
>> suggested is still a problem in that case?
> 
> I cannot really tell.  Maybe, if you need different loggers in
> different unit tests and mix in multi threading to make your test
> suite finish faster. :-)
> 
> But I do know that global state is problematic.  I guess you can find
> plenty of evidence on the web (or reason about it for yourself /
> according to your own code).  It should be used with extra care.  I
> try to avoid it whenever possible and that approach has served me
> well.

I'll keep that in mind.  Thanks for the tips. ;-)

-Jeremy