Ubuntu test fixes

Author: mrvisscher

.github/workflows/testing.yaml

@@ -25,6 +25,17 @@ jobs:
         with:
           python-version: ${{ matrix.py-version }}
 
+      - name: Install linux dependencies
+        if: ${{ matrix.os == 'ubuntu-latest' }}
+        # https://pytest-qt.readthedocs.io/en/latest/troubleshooting.html#github-actions
+        run: |
+          sudo apt install -y libxkbcommon-x11-0 libxcb-icccm4 libxcb-image0 \
+            libxcb-keysyms1 libxcb-randr0 libxcb-render-util0 libxcb-xinerama0 \
+            libxcb-xfixes0 xvfb x11-utils glibc-tools;
+          /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 +render -noreset;
+
       - name: Update pip & install testing pkgs
         run: |
           python -VV