Prohibiting depencency fetching (for test target particularly)

My use case is packaging python modules as distro native packages (in my case, FreeBSD ports). For this case, for the sake of security, consistency and reproducibility, I need to unconditionally disallow dependency fetching (which is the case at least for python setup.py test) as all dependencies must be installed from the mentioned ports system, and there should be a failure if some are missing. I've found --no-deps argument for easy_install which seem to do just what I need, however I couldn't find any way to pass easy_install arguments via python setup.py test. Could it be that I'm missing something, or is this not supported? In the latter case, this should be implemented.

Start by tracing the python setup.py test entry point and how it invokes easy_install; inspect how the --no-deps option could be passed or enforced. Done means dependency fetching is disabled for the test target and missing installed dependencies cause a failure.