Unix Domain Socket support in ContainerPgRule

[tsegismont]

Replaces embedded Pg with container testing for Unix domain sockets

[tsegismont]

@vietj can you please take a look and try on your machine? Thank you

[vietj]

this isn't something we want to do because it cannot be tested on OS X since Docker for Mac is not able to share domain sockets, see docker/for-mac#483

[vietj]

it does not work on OS X because Docker for Mac does not support sharing domain sockets, that's the reason we kept this rule

[tsegismont]

Ok, let's put this on hold then

[vietj]

yes, that's unfortunate, you can give your +1 on the Docker GitHub issue to make it progress.

[BillyYccc]

This is in fact duplicated of #520.
I wonder if we could set up a specific database with unix socket in the CI for tests.

[tsegismont]

Ha, I had not noticed @BillyYccc , sorry.

@vietj on second thoughts, do we absolutely need an automated test for BSD and the likes? There is nothing specific in our code, we just pull a different dependency. And CI validates it works on Linux.

What are the chances something goes wrong with kqueue specifically? And if we get a bug report, there is still the option to start a server installed from brew and test manually in the background.