When the python interpreter for an environment is in a deep directory hierarchy (in my case due to a jenkins matrix with 4 axis), tox will make a pip call like:
The shebang in this file has the full path for the python interpreter in the virtualenv. In one of my failing tests it was:
With a path length of 131 that exceeds linux's limitation of 127. Patching tox to call
$PYTHON_BIN_PATH $PIP_BIN_PATH instead of just
$PIP_BIN_PATH solves the problem.