RuntimeError: could not open display

Question

I have a unit test which contains

import gtk

Which contains unit tests to test the signal handler and GUI classes. This works fine when I run py.test from the shell as I have an X11 display connected. However, when I try to run tox, I get:

______________________ ERROR collecting tests/test_gui.py ______________________
tests/test_gui.py:17: in <module>
    from rprs_bootstrap.gui import GUI
src/gui.py:12: in <module>
    import gtk.glade
.tox/py27/lib/python2.7/site-packages/gtk-2.0/gtk/__init__.py:64: in <module>
    _init()
.tox/py27/lib/python2.7/site-packages/gtk-2.0/gtk/__init__.py:52: in _init
    _gtk.init_check()
E   RuntimeError: could not open display
!!!!!!!!!!!!!!!!!!!! Interrupted: stopping after 1 failures !!!!!!!!!!!!!!!!!!!!
=========================== 1 error in 0.34 seconds ============================
make: *** [tox] Error 2

I could start a Xvfb server from within tox.ini but that seems inelegant. Any suggestions?

Answer 1

Use pytest-xvfb

which

[...] runs your testsuite with Xvfb to avoid popping up windows during GUI tests or allow them to run on systems without a display (like a CI).

To install:

pip install pytest-xvfb