Re: [PATCH 1/2] t5516/t5601: avoid using `localhost` for failing HTTPS requests

> > Let's instead use an IPv4 address that is guaranteed never to offer a
> > web server: 224.0.0.1 (which is part of the IP multicast range).
>
> This feels pretty magical. I think it would be pretty unlikely for it to
> have a web server, but I wouldn't be surprised if there are systems
> where we get similar IP-routing hangs.
>
> Is there a reason not to move all of these tests into t5550 or t5551,
> where we have a real http server? That would be less magical, and then
> this first test:
>
> >  test_expect_success LIBCURL 'fetch warns or fails when using username:password' '
> > -	message="URL '\''https://username:<redacted>@localhost/'\'' uses plaintext credentials" &&
> > -	test_must_fail git -c transfer.credentialsInUrl=allow fetch https://username:password@localhost 2>err &&
> > +	message="URL '\''https://username:<redacted>@224.0.0.1/'\'' uses plaintext credentials" &&
> > +	test_must_fail git -c transfer.credentialsInUrl=allow fetch https://username:password@224.0.0.1 2>err &&
> >  	! grep "$message" err &&
>
> could be more robust. It would actually check that we succeeded in using
> the URL.