[Zope-dev] zope.component test isolation

[Wolfgang Schnerring]

Hi,

it seems to me this has stalled somewhat, so I wanted to ask what
people's conclusions are.

* Wolfgang Schnerring <ws at gocept.com> [2011-03-26 13:41]:
> * Martin Aspeli <optilude+lists at gmail.com> [2011-03-26 11:22]:
>> On 26 March 2011 08:11, Wolfgang Schnerring <ws at gocept.com> wrote:
>> I don't think a fixture of "package foo's configuration except
>> component X and Y" is all that useful.

Whether the the "unregister" use case is useful remains debatable, but I
personally don't care all *that* much for it, so if the consensus is
that it's overkill I'll go along I guess.

I do care quite a bit for proper getSiteManager() support...

>> We do definitely need to allow the global site manager to be stacked
>> (which you can achieve with __bases__ as in plone.testing,
>> unregistration notwithstanding). But once you do that, the rest is
>> pretty easy. The local site manager will always have the global as one
>> of its (nested) __bases__.
>
> I'm sorry, but no, it isn't that easy. When the only local site
> consumer is zope.site, well, maybe. But please think of this in terms
> of zope.component *only*.
>
> Its API is getSiteManager.sethook(callable), and AFAICT the contract
> is that the return value of callable must provide IComponents
> (briefly: get* and register*). Nowhere does it say that you have to
> delegate back to the global registry, and neither it should. To bring
> up Pyramid once again, they explicitly don't, because they want to
> allow several applications (thus, several registries) coexisting in
> the same process.
>
> And since we can't assume this delegation, I think there is no other
> way to properly do the stacking than to bend getSiteManager.

... as described here, though. And I wonder if I'm missing something,
because to do that properly looks like quite the can of worms to me.

So, how can we proceed here? Should I (and Thomas) try to get a
proof-of-concept implementation of this based on plone.testing? Or should
we think about what it takes to merge most of plone.testing's ZCA
support into zope.component itself first?

Wolfgang