diff --git a/python-matplotlib.spec b/python-matplotlib.spec
index 0797100..2dc1d64 100644
--- a/python-matplotlib.spec
+++ b/python-matplotlib.spec
@@ -477,13 +477,15 @@ echo "backend      : %{backend}" > matplotlibrc
 MPLCONFIGDIR=$PWD \
 MATPLOTLIBDATA=%{buildroot}%{_datadir}/matplotlib/mpl-data \
 PYTHONPATH=%{buildroot}%{python2_sitearch} \
-     xvfb-run -a %{__python2} -m pytest --pyargs matplotlib -m 'not network' -k 'not test_polycollection_close' -ra
+     xvfb-run -a -s "-screen 0 640x480x24" \
+         %{__python2} -m pytest --pyargs matplotlib -m 'not network' -k 'not test_polycollection_close' -ra
 
 %if %{with_python3}
 MPLCONFIGDIR=$PWD \
 MATPLOTLIBDATA=%{buildroot}%{_datadir}/matplotlib/mpl-data \
 PYTHONPATH=%{buildroot}%{python3_sitearch} \
-     xvfb-run -a %{__python3} tests.py -m 'not network' -ra
+     xvfb-run -a -s "-screen 0 640x480x24" \
+         %{__python3} tests.py -m 'not network' -ra
 %endif
 %endif # run_tests