What's a simple way to set up a private network of a few peers for testing purposes?

[Alessio Vanni]

Hello,

as per the subject, I'm looking for a way to set up a small independent
network of peers to test an application.

What I'm looking for is primarily for this network to exist
independently from the normal global GNUnet network that peers connect
to when using the default configuration.

I don't really care if the testing can be automated or if it has to be
handled manually, or if there are concerns about speed or stability; as
long as the above condition holds I'm fine with anything. I can probably
work around issues, if there's a need to.

I know that GNUnet has TESTING and TESTBED, but I can't tell if whatever
they do happens on a dedicated network of peers or if they still make
contacts with the outer world, in addition to having to study the API,
so I haven't yet tried them.

The main reason is that I have some test data that I don't want to (and
for some of it "can't") distribute on the global network, but I can't
run any tests without having two or three other connected peers.

If it makes things different, as briefly said in the subject, the
network can just be a total of three peers connected with each other, as
that is enough to check if the application works regardless of other
metrics, so I don't really need things that might make setting things up
more complex.

Thanks,
A.V.

P.S. to be honest, "just use TESTBED" would be the ideal answer, but
since I need independence and I don't know if TESTBED does it, I thought
I'd ask before spending time on something that I don't need.