When using tox version 2.3.1 and pip version 8.x I get the following error when tox attempts to install my "deps" (
deps = -rtest-requirements.txt).
no such option: --download-cache ERROR: could not install deps [-rtest-requirements.txt]; v = InvocationError('/home/travis/build/waylan/Python-Markdown/.tox/py27/bin/pip install --download-cache=/home/travis/build/waylan/Python-Markdown/.tox/cache -rtest-requirements.txt (see /home/travis/build/waylan/Python-Markdown/.tox/py27/log/py27-1.log)', 2)
It is clear that tox is calling
pip install with the
--download-cache flag, which was deprecated in pip version 6.0 and removed in 8.0 (see release notes). Interestingly, after seeing the error on Travis, I tested on my local machine by first upgrading pip to version 8 before upgradting tox and on tox version 2.2.1 no error was raised with pip version 8. However, once I upgraded tox to 2.3.1 the error appeared.