Tox will not force installation of the package under test on initial virtualenv creation

Issue #343 on hold
Amber Brown
created an issue

Twisted includes some tests that operate PyDoctor, and PyDoctor depends on Twisted. So, if I put "pydoctor" under deps, and then do tox -r -e myenv, it will install Twisted from PyPI. This is fine, but it won't install the Twisted under test (which, right now, has the same version number), meaning that I'm actually testing the released 16.3.0, not my 16.3.0+some commits.

If I subsequently run tox -e myenv, it will correctly install the Twisted under test into the environment.