different approach to activate xvfb

Author: chrissimpkins

.github/workflows/python-ci.yml

@@ -9,6 +9,8 @@ jobs:
       matrix:
         os: [ubuntu-latest]
         python-version: [3.9]
+    env:
+      DISPLAY: ":99.0"
 
     steps:
       - uses: actions/checkout@v2
@@ -22,7 +24,8 @@ jobs:
           python -c "import struct; print(struct.calcsize('P') * 8)"
       - name: Install testing dependencies
         run: |
+          python -m pip install --upgrade pip setuptools wheel tox tox-gh-actions pytest pytest-qt
           sudo apt install libxkbcommon-x11-0 libxcb-icccm4 libxcb-image0 libxcb-keysyms1 libxcb-randr0 libxcb-render-util0 libxcb-xinerama0 libxcb-xfixes0
-          python -m pip install --upgrade pip setuptools wheel tox tox-gh-actions pytest pytest-qt pytest-xvfb
+          /sbin/start-stop-daemon --start --quiet --pidfile /tmp/custom_xvfb_99.pid --make-pidfile --background --exec /usr/bin/Xvfb -- :99 -screen 0 1920x1200x24 -ac +extension GLX
       - name: Run tox tests
         run: python -m tox