How to check if apt proxy configuration is correct?

Question

I have to use a proxy server which requires authentication. So, I need to update the apt.conf file to include my proxy settings. All fine. What I need is to check that the configuration is correct so that when I try apt-get update, I'll connect to the relevant repositories, etc.

Is there a way to check this without downloading anything to the PC (without update, install, upgrade, etc.)? In short: I'm looking for a way to just ping the repositories without any actual download happening.

Any other ways to validate the apt proxy settings is also welcome...

Edit: I read the manual but I couldn't see the functionality to be available by a simple option/flag. Maybe there is a hack?

Update: So, far the only solution I have is to apt-get install a tiny package and then remove it afterwards. But, I don't really like this approach. What if the package is already installed on the machine? Will apt-get still connect to the repositories (to check if the package is up-to-date)?

Update2: Apparently there is no solution to all the requirements I put in the question. I'll pick the answer with the closest to what I want.

Answer 1

apt-get update is the way I'd do it. It hits all repositories.

Failing that, you could pretend to force the reinstallation of a small package with apt-get clean; apt-get -d --reinstall install hostname (this will mark the package as to-be-installed, so pick a package that's already installed).