chore(ci): disable external network calls

[miketheman]

As some tests spin up a local server, allow clients to communicate with
local addresses only.

Refs: https://pypi.org/project/pytest-socket/

[ichard26]

Does this work in subprocesses? pip's functional test suite makes very heavy use of subprocesses (sometimes nested 2-3 times over). Also we use pytest-xdist, so it should work with that as well.

In general, I'm 👍 with the idea. Once the test suite is in better shape, we should enforce test hygiene by requiring tests to opt-in into external network access.

[ichard26]

Does this work in subprocesses? pip's functional test suite makes very heavy use of subprocesses (sometimes nested 2-3 times over). Also we use pytest-xdist, so it should work with that as well.

Given that the diff only really touches the unit tests, no, it does not work in subprocesses. There are certainly many more being performed in the functional tests. This patch is probably still a good idea for our unit tests though.

[miketheman]

Does this work in subprocesses?

Probably not! That's not something I've encountered needing before. Since the plugin hooks into Python's socket library, any subprocess is likely to not have this applied, as they'll get their own Python context. That might make this a less-valid approach for this test suite.

Also we use pytest-xdist, so it should work with that as well.

pytest-socket isn't currently tested with xdist, nor do the tests it runs test the xdist plugin, but experientially running it for warehouse over 4k+ tests works just fine.

In general, I'm 👍 with the idea. Once the test suite is in better shape, we should enforce test hygiene by requiring tests to opt-in into external network access.

Glad to hear it! This change might not be the correct implementation, given the subprocesses question. I'll mull on how this might apply to subprocesses - but if you've got some ideas, please share!