Description
Test suite sometimes fails or freezes when all tests pass.
example output for failure after passing:
=================== 561 passed, 4 skipped in 919.07 seconds ====================
ERROR: InvocationError: '/home/travis/build/apache/incubator-ariatosca/.tox/py27/bin/pytest tests --ignore=tests/end2end --ignore=tests/orchestrator/execution_plugin/test_ssh.py --cov-report term-missing --cov aria'
___________________________________ summary ____________________________________
ERROR: py27: commands failed