It seems like there's an upstream bug in the "lpstat" command. We need
to specify the server's port.
Further information: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=711327
[root@client:~]# lpstat -H
/var/run/cups/cups.sock
[root@client:~]# lpstat -h server -H
/var/run/cups/cups.sock:631
[root@client:~]# CUPS_SERVER=server lpstat -H
server:631
[root@client:~]# lpstat -h server:631 -H
server:631
You can now run a test in the nixos/tests directory directly using
nix-build, e.g.
$ nix-build '<nixos/tests/login.nix>' -A test
This gets rid of having to add the test to nixos/tests/default.nix.
(Of course, you still need to add it to nixos/release.nix if you want
Hydra to run the test.)
