run tests in offscreen platform

Author: rettigl

.github/workflows/testing_coverage.yml

@@ -29,6 +29,7 @@ jobs:
       # Run pytest with coverage report, saving to xml
       - name: Run tests on python 3.12
         run: |
+          export QT_QPA_PLATFORM=offscreen
           pytest --cov --cov-report xml:cobertura.xml --full-trace --show-capture=no -sv -n auto tests/
 
       # Take report and upload to coveralls

.github/workflows/testing_multiversion.yml

@@ -34,4 +34,5 @@ jobs:
 
       - name: Run tests on python ${{matrix.python-version}}
         run: |
+          export QT_QPA_PLATFORM=offscreen
           pytest --full-trace --show-capture=no -sv -n auto tests/