Installing 9.6 RC on Ubuntu

I'm trying to install 9.6 RC1 on Ubuntu 16.04 Xenial on my laptop and it
seems broken.

Installation of 9.6 RC1 on Centos was straightforward by comparison - just
add the 9.6 yum package and install. Unfortunately Ubuntu seems
second-class by comparison.

I already have /etc/apt.repos.d/pgdg.list with:
deb http://apt.postgresql.org/pub/repos/apt/ xenial-pgdg main

This works and I previously installed the PGDG 9.5 package without issue.
Apt lists numerous 9.6 support packages (unit, repmgr, repack, plv8, ...)
but with unsatisfied dependencies due to the lasck of postgresql-9.6.

I tried adding -testing to the repo but no joy:
deb http://apt.postgresql.org/pub/repos/apt/ xenial-pgdg-testing main

Is packaging just not complete or am I missing something? (I had hoped that
getting configured for testing would be more friction-free.)

Cheers,
Steve