tox: InvocationError without further information

It might happen that your tox run finishes abruptly without any useful information, e.g.:

ERROR: InvocationError:
'/path/to/project/.tox/py36/bin/python test --addopts --doctest-modules'
___ summary _____
ERROR: py36: commands failed

pytest-qt needs a DISPLAY to run, otherwise Qt calls abort() and the process crashes immediately.

One solution is to use the pytest-xvfb plugin which takes care of the grifty details automatically, starting up a virtual framebuffer service, initializing variables, etc. This is the recommended solution if you are running in CI servers without a GUI, for example in Travis or CircleCI.

Alternatively, tox users may edit tox.ini to allow the relevant variables to be passed to the underlying pytest invocation:


Note that this solution will only work in boxes with a GUI.

More details can be found in issue #170.

xvfb: AssertionError, TimeoutError when using waitUntil, waitExposed and UI events.

When using xvfb or equivalent make sure to have a window manager running otherwise UI events will not work properly.

If you are running your code on Travis-CI make sure that your .travis.yml has the following content:

sudo: required

  - sudo apt-get update
  - sudo apt-get install -y xvfb herbstluftwm

  - "export DISPLAY=:99.0"
  - "/sbin/start-stop-daemon --start --quiet --pidfile /tmp/ --make-pidfile --background --exec /usr/bin/Xvfb -- :99 -screen 0 1920x1200x24 -ac +extension GLX +render -noreset"
  - sleep 3

  - "herbstluftwm &"
  - sleep 1

More details can be found in issue #206.