Network access during build

Hey!

One of the package that I maintain (python-asyncssh) makes a DNS request
during build and expects it to fail. Since Policy 4.9 forbids network
access (in a rather confusing wording "may not"), I got this serious
bug:
 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=830568

The fix is easy: just disable the test.

However, I have a hard time to find this useful for anyone. To sum up:

 - patching the test suite requires maintaining the patch forever
 - both pbuilder and sbuild are using an isolated network namespace
 - package builds reproducibly with or without network access

I have the impression that enforcing every word of the policy in the
hard sense can bring endless serious bugs. This particular occurrence
affected about 70 packages. I appear as a bad maintainer because I don't
feel this is an important bug.

Any thoughts?
-- 
Use uniform input formats.
            - The Elements of Programming Style (Kernighan & Plauger)