run-tox.sh hides errors
run-tox.sh runs the check tests for several python tools. It runs tox with stdout and stdout redirected to <virtualenv>/tox.out, and greps the result for "InterpreterNotFound". Sadly, if that's the error (say, running on a host with no python3.4 installed), there's no indication to the test run of the failure reason, because it's only held in tox.out.
Guess who spent days trying to track this down?